How did Indonesia and Malaysia become majority-Muslim?
Reproduction of an unknown Redditor's excellent answers
In the course of my background research for the “Dharma” series (here’s Part 1, Part 2, Part 3, Part 4 and Part 5), I came across a Redditor’s responses from six years ago (no longer active so the username now shows as “[deleted]”) who wrote extensively with references that highlights how Dharma - be it Sanatana or Buddhism - were not extant in the quite the same manner in Southeast Asia as they were in the Subcontinent and China. While this person’s responses were predominantly on Indonesia, parallels are made with respect to Malaya as well. Thus, the chain of events are likely to have been the same with Malaya as well.
There were a couple of assertions made that were incorrect as the “Dharma” series indicated and which seemingly rested on Western Orientalist/colonial pseudo-scholarship tropes. Firstly, the Redditor mentions that “Hinduism really isn't one religion at all”. Textual research disproves this handily: Sanatana - from the Vedas to the hundreds of Puranas unknown millennia later - has always been pluralistic: be it on the matter of deity, choices of deity, prayer, ritual, worship, philosophy, et al as long as they were built on the metaphysical truths of the Vedas. The faith divined numerous forms of hierarchies and fail-safes to address this plurality for its masses.
Secondly is the assertion that Islam in the East populated vacant lands and became a form of “civilization”. This might be true in the regions discussed but the sword was never far away in the Subcontinent. Recent news about efforts to reclaim Dharmic shrines from under Islamic structures as well as the Turkic invaders’ own accounts is proof aplenty, despite the best efforts of Marxian historiographers and the class of schism-seekers who venerate them to derive their own false authority.
However, the Redditor does profess to know little about the Subcontinent. Fair enough, in that case.
Finally, the Redditor’s responses may/may not stand the test of time: the religious history of Southeast Asia is an active field of study so the conclusions derived by this person may not hold true in the face of new evidence. The Redditor’s responses are in two parts: here below and in the “Addenda”, which also includes material from some other noteworthy contributors.
Note to my subscribers: this isn’t my work so I haven’t sent this through email.
TL;DR: Shit was complicated.
Actual TL;DR: Rulers converted for economic, political, and personal reasons. Not much work has been done on popular conversion, but so far it seems that the government and Sufis both helped spread Islam on a popular level. The new religion was perceived as magic, provided solace in a changing world, and finally became just a part of life.
For reference, Melaka (Malacca) is opposite Riau and Patani is the part of Thailand that juts out into the map on the upper left.
What happened, and where and when?
This is just the background story, summarized well in most general histories of Southeast Asia like The Cambridge History of Southeast Asia: Volume 1, A History of Early Modern Southeast Asia by the Andayas, History of Modern Indonesia from c. 1200 by M. C. Ricklefs, etc. I'm mainly writing by memory here, so there will probably be mistakes.
Islam has been in Southeast Asia since almost the beginning of the faith. But the first major kingdom to become Muslim (that we know of) was Samudra-Pasai in what is now Aceh, which adopted Islam in the late 13th century. Other port-states nearby followed suit. The real major breakthrough was the firm establishment of Islam in the Malay sultanate of Melaka, which held a lose hegemony over the Straits of Melaka that link East Asia to the rest of the world (the Islamization of the Melaka dynasty was a long-term process but was largely completed by 1446). From Melaka, the hub of commerce in Southeast Asia, Islam followed the trade routes east. The Portuguese capture of the city of Melaka in 1511 only aided the Islamization of the Western Archipelago as Malay sultanates, especially Aceh, became more fervently Islamic in order to oppose the stridently anti-Islamic Portuguese. Aceh had become the preeminent city in the Straits of Melaka by the mid-16th century and a center of missionary activity. It was through a Malay medium that Brunei and ultimately South Sulawesi were Islamized, for example.
East in Java, there were aristocratic Muslims even during the height of the Hindu-Buddhist empire of Majapahit. But Majapahit was in political decline throughout most of the 15th century while the ports of the north coast of Java grew in power and became more and more Muslim. Slowly the coast broke away from Majapahit. One of these independent ports was Demak, whose first sultan was a Majapahit official. In 1527 Demak killed off a nearly moribund Majapahit - but despite the religious change, Demak sought to portray itself as the rightful successor to the heritage of Majapahit. Anyways Demak collapsed soon after. The next state to have dominance over most of the island was the Muslim kingdom of Mataram, but it was not until the 1630s that the 'mystic synthesis' of Islam and pre-Islamic philosophy really began.
Islam made significant progress further east as well. Muslim chiefs were ruling some parts of the eastern Archipelago as early as 1310! By the time the Portuguese arrived in the early 16th century, the Spice Islands of Maluku were largely ruled by Muslim kings. By the mid-16th century there was every indication that Islam could and would spread further north and east, into the northern and central Philippines, but this movement was halted by the Spanish conquest there. So the last major area of precolonial Indonesia to become Muslim would be South Sulawesi, where all major royal dynasties converted from 1605 to 1611.
Preliminary notes:
The greatest single issue with discussing Islamization in Southeast Asia is a simple lack of sources. The climate isn't great for the survival of early manuscripts, while archaeology still has a long way to go. (Surviving) local sources are rarely contemporaneous and generally stay elite-focused, "provid[ing] no adequate account of the conversion or the process of Islamization of the population." European sources are marred by at least three flaws; first, they're biased against Islam and Southeast Asia; second, they're biased towards things of commercial interest for Europeans; third, they're biased towards the state of affairs in the urban ports, not in the agrarian interior of most islands. There are Chinese and other Muslim sources, but many haven't even been published.1
This is then complicated by Orientalism. Stamford Raffles, British scholar and conqueror of Java, was perplexed about how low Java had 'fallen.' Its great Hindu-Buddhist monuments clearly proved that the Javanese weren't racially inferior. But now, Raffles lamented, "the grandeur of their ancestors seems like a fable in the mouth of the degenerate Javan" because "Mahometan institutions had considerably obliterated their ancient character, and had not only obstructed their improvement, but had accelerated their decline." This was an implicit justification of imperialism; Southeast Asia would be restored to its "ancient character" by enlightened Europeans.
This tradition continued in Western scholarship until quite recently and meant that studies of Islamic Southeast Asia had the tendency to focus on the 'exciting' Hindu-Buddhist past, while Southeast Asian Islam was dismissed as not being real Islam.2 While this attitude has thankfully changed in the past few decades, its legacies linger on and, together with the more serious problem of lack of sources, contribute to gaps in the scholarship. The field of Islamization remains ripe for research, and there's a lot of uncertainty with every theory seeking to explain the process.
So just note that almost everything I say from now on has been challenged by one historian or another.
Notes about my answer:
When I wrote this answer in my private subreddit, RES had a bug making all links be followed by a line break. If this happens, just reload and hope for the best.
I'll try to make it as comprehensible as possible for people who don't know much about Southeast Asia and link to Wikipedia when possible, but it's going to be tough.
I will often use 'Southeast Asia,' 'Archipelagic Southeast Asia,' and 'Indonesia' interchangeably. All I mean is the general area I painted red here.
My answer is centered around themes, not chronology or geographic area.
I should have stressed this more in my answer, but these themes are common themes, not universal ones. There will be generalizations in my answer, so I'll say it now: Southeast Asia is an extremely diverse area and the adoption of Islam was different for every single place.
Sourcing is somewhat haphazard. I sourced all quotes and facts people might not believe (e.g. the casualty rates in the Battle of Ayutthaya in 1686) and at the end of a section I tried to include something like 'for more on this, see sources X, Y, and Z.' But overall I sourced when I felt like it, so feel free to challenge me on that.
Unfortunately, I will not spend much time discussing how the historiography of one theory or another has changed. This means that I might sound a lot more confident about something than I actually am. Keep in mind that as I said above, "almost everything I say from now on has been challenged by one historian or another."
Quality of writing varies depending on what mood I was in the day I wrote it.
I. Why did rulers convert?
It is widely agreed that the king/queen was usually among the first people anywhere to convert to Islam. Merchants are the only people who might have frequently beaten them to the punch. Many local sources agree on this too, like a chronicle from eastern Borneo which says the king was first to convert, then his nobles, and finally the common people only after all the nobles were Muslim. Elite conversion and state support for Islam were critical to conversion lower down on the ladder. And unfortunately, most of our sources present an elite perspective on religion, meaning there's more certainty compared to popular conversion. With all this in mind, it seems fitting to start off by asking ourselves why Southeast Asian rulers converted to Islam.
But before, let's look at the two r/AskHistorians FAQ answers that do address elite conversion to Islam in Southeast Asia. This answer claims that rulers converted "depending on who the trading partner du jour was."3 This answer4 claims that "conversion to Islam began because leaders sought inclusion in vital Muslim trading networks." Just by looking at the FAQ, it seems like there's a consensus: elite conversion happened because economics, period.
But was it really just for money? In the following five posts, I'm going to argue no. Trade mattered a lot. But the political benefits of Islam mattered as well. One final post will bring up an example of a genuinely devout Muslim ruler to remind us all that people do not just convert for practical benefits. We shouldn't get caught up too much in 'big picture' arguments to forget the human side of conversion.
The role of commerce
Ever since a 16th-century Portuguese writer, Tome Pires, blamed "the cunning of the merchant Moors" for the spread of Islam, the 'trade theory' has been a mainstay of answers to the question of Southeast Asian Islam ever since. But there are variants to this model. A once popular paradigm is now entirely discredited in academia but still pops up from time to time in places like /r/ELI5 (according to r/Indonesia, it's apparently the theory presented by Indonesian textbooks). I'll quote the ELI5 answer in full since it actually sums up this paradigm pretty well:
South East Asian area has always been a notable trading post. When ships became popular, Middle East merchants sailed to SE Asia to buy or trade stuffs. At that time, the prevalent religion there was a mix of Hinduism and Buddhism. which enforced caste system. When the local population heard about Islam, it was considered a more attractive replacement since it doesn't have concept of caste. Everyone is equal in the eyes of Islam's God. From then on, the religion spread very quickly and is still the most prevalent religion in Malaysia and Indonesia.
Yet there is very little evidence that Southeast Asian Islam was a truly egalitarian religion in practice. For example, society in South Sulawesi was divided into three main 'castes': the white-blooded nobility who claimed divine descent, the freemen, and the dependents (slaves or serfs). This system survived Islamization entirely intact - so much for everyone being equal! And even in 'Hindu' areas, caste existed only as a concept in elite thought, not as an actual thing.5 And ultimately, virtually all conversion to Islam involved first the ruling elite, and then the majority of the population. So this is bunk.
But there's another more sensible variant of this theory, which has been in currency since at least the 1940s when young Dutch historian J. C. Van Leur wrote a book titled Indonesian Trade and Society. Leur's story goes more like this:
Muslim merchants began to visit an Indonesian port-kingdom. The king hired a Muslim harbormaster to encourage his coreligionists to keep on trading, since their mercantile activities strengthened his authority. The harbormaster recommended that he build a mosque for the Muslims so that the Muslims would find the kingdom a welcoming place and keep coming. More Muslims came, and so more and more concessions were gradually made. Meanwhile, the more commercially oriented subjects of the king were already converting to integrate themselves into the wider Islamic trading network that stretched across the entire Indian Ocean. Eventually the king himself converted. The ports that were commercially competing with this kingdom saw that their hated rival was getting a lot more Muslim trade ever since they converted, and decided to convert themselves.
This makes a fair deal of logical sense. But let's ask ourselves a few questions. First, was there a large increase in Muslim trade when Islamization really kicked off? That's where the 'Age of Commerce' paradigm comes into play. Around twenty years ago, historian Anthony Reid wrote two books titled Southeast Asia in the Age of Commerce, where he argued that around 1400 there was a great upsurge in foreign commerce in Southeast Asia. This is evident if we look at the well-documented European imports of the fine spices, which in the 15th century were exported to Europe almost entirely through the activities of Muslims, especially since much of the Indian commercial diaspora appears to have converted to Islam in the 14th century. Here's the chart of estimated European spice imports, almost all of which would have been through Muslim hands:
Portuguese entry into the Indian Ocean in the early 16th century, especially their capture of Melaka in 1511 and their attempt to block the Red Sea and Persian Gulf, was a shock assault on the Muslim spice trade. But with the patronage of the Ottoman empire trade quickly recovered, and by 1536 there was already an "immense swarm" of spice-bearing Muslim ships sailing west and the Portuguese were helpless to stop them. By the mid-16th century the Muslim spice trade was not only greater than the Portuguese spice trade, but had also reached volumes never before seen.6 Ottoman subjects were serving as royal agents in the spice island of Ternate, 10,646 kilometers (6,615 miles) southeast of Istanbul!7
Another surprising source of Muslim trade were Chinese Muslims who escaped the chaos of 14th-century civil war (the Yuan-Ming dynastic transition) by fleeing to Southeast Asia. There were large Chinese Muslim communities throughout the western and central Archipelago and some ports were even de facto under Chinese rule when Zheng He's treasure fleet arrived. The first sultan of Demak had a Chinese mother, while elements of Chinese temple architecture have been reported in the earliest Javanese mosques. The role of Chinese Muslims in early Southeast Asian Islam is heavily disputed, but suffice it to say that Chinese were a part of the Muslim trading community until their assimilation into local society once China withdrew from the oceans.8
But perhaps the most important Muslim trading community was Southeast Asians themselves. By the early 16th century the Malay and Javanese commercial diasporas were already quite Muslim. I suspect that Southeast Asian merchants were among the first to become Muslim; after all, many Indian merchants became Muslim even while their homelands remained almost entirely Hindu. Converting to Islam was an easy way for an ambitious businessman to vastly improve relations with Muslim merchants, and many Southeast Asians associated Islam with wealth. One of the Spanish conquistadors of the Philippines reported that local Muslims "worshipped" gold and that some non-Muslims who didn't even know who Muhammad was still refused to eat pork because they thought not eating pork was what made Muslims so rich. Competition with the infidel Portuguese intent on destroying Islam may only have hardened local merchants' commitment to the faith. And these Muslim Southeast Asians were everywhere to the point that Malay was (and still is) the lingua franca of Southeast Asia. Despite the presence of Ottomans, the most important merchants in Maluku in the 16th century were Javanese. Similarly, there is evidence of a Malay presence in South Sulawesi since at least around 1480 while Indians or Chinese did not arrive (at least not in large numbers) until the 17th century.9
Second, did gradual concessions to Islam really happen? It would appear so. For instance, the Hikayat Patani, a Malay chronicle from Patani (now part of Thailand), says that the first Muslim ruler of Patani, who lived in the 15th century, abstained from pork and worship of idols. But otherwise, "he did not alter a single one of his kafir [non-Muslim] habits." It wasn't until the 16th century that the first mosque was built, and this too might have been more for show than for piety since the Hikayat specifies that it was built "because without a mosque there is no sign of Islam." Even at this point, a century after the king of Patani had stopped eating pork, "heathen practices such as making offerings to trees, stones, and spirits were not abandoned by" the Patanese. Or in South Sulawesi, the kingdom of Gowa built their first mosque a generation before the formal adoption of Islam "for [Muslim Malay] traders who came to live."10
Making these concessions to Islam was especially important because agricultural resources of many kingdoms were limited. Trade was crucial to the maintenance of both enormous urban populations and central authority over provincial underlings. So in a situation where "the king is a pagan; the merchants are Moors," which the Portuguese said of Brunei in 1514 but must have been the case in many other places, it made sense for the king to treat the "Moors" as well as possible, up to converting to Islam.
Third, were merchants and economics really enough for Islamization? This is the toughest question to answer. There's some evidence to say yes. Van Leur characterized Malay and Javanese merchants as "peddler missionaries," and Javanese merchants in central Maluku were indeed invited to stay for some time to teach the Muslim faith to the locals. As mentioned, early European reports stress the influence of Muslim merchants in conversion. On the other hand, local records barely mention the role of trade in Islamization. After all, the primary goal of Muslim merchants was to make money, with successful proselytizing just a bonus.
For a more in-depth look at how concessions to Islam do not necessarily lead to conversion, let's look at the kingdom of Arakan (you might know a bit about it if you've been following the news on the ongoing ethnic cleansing of Muslims there). Arakan, located on the mountainous western coast of modern Myanmar, was also quite dependent on trade. So by the 17th century there was a significant Bengali Muslim community in Mrauk U, the capital of Arakan. Retaining Muslim support and not losing them to competing ports were very important to Mrauk U's kings because Arakan apparently had no rich indigenous merchants at all. Harbormasters in Mrauk U were very frequently Muslims, while in the 1630s a Muslim eunuch ran the stage in the kingdom. There was some conversion to Islam among native Arakanese, mostly involving rich Muslims converting their slaves. Arakanese kings adopted trappings of Mughal court culture, building mosques and even putting the Six Kalimas in coins.
However, popular acceptance of Theravada Buddhism in Arakan grew rapidly under royal patronage at the same time that they were making these coins and building mosques. The adoption of Islamic culture may have been justified through the Buddhist ideal of the universal ruler, which allowed the Arakan king to patronize his Muslim subjects as well as the Hindu minority and the predominant Buddhist majority. So the ruler of Arakan could simultaneously be a sayyid (descendant of Muhammad), kshatriya (member of the Hindu ruling caste), and a distant relative of the Buddha. But in the end Arakan remained a Buddhist kingdom, although it was an extremely tolerant one.11
So in an alternate timeline we could imagine a world where the rest of Southeast Asia took the Arakanese path, with Hindu-Buddhist rulers adopting bits and pieces of Islam but never really converting and the majority of the population staying non-Muslim. And being convenient for Muslims was a lot more important for Arakan than in places like Java, where most people were farmers, or some of the Spice Islands, which would have attracted Muslim merchants even had they been Satan's vacation home.
Muslim trade was absolutely necessary for Islamization, if only because Southeast Asia wouldn't have been acquainted with Islam in the first place had there been no Muslim merchants. Muslim-dominated trade routes were also highways for those with a more spiritual vocation, like Sufis, to reach Southeast Asian ports. But was trade the only thing necessary? It wouldn't appear so.
(P.S. Of course many Southeast Asian Muslims are assimilated descendants of Persians, Indians, Chinese, etc. This alone can't explain why Indonesia is majority Muslim since there clearly wasn't widespread population displacement like in the US, so I didn't go in-depth on that.)
Islam and royal authority
In 1670, a Malay poet in a South Sulawesi court describes his king in these terms:
My lords, hear a humble homage
To the most magnificent king;
Perfect in gnostic understanding ['arif]
Caliph of [the annihilators of being.]
--
By the grace of God and the intercession of the Prophet
Caliph of God in the two states; [the two kingdoms of Gowa and Talloq]
Beloved by God and His friends [wali]
There was joy and wealth in both realms.
[Translation in Gibson 2007, Islamic Narrative and Authority in Southeast Asia]
This was quite a new way to depict a South Sulawesi ruler, where rulers were often conceived more as servants of the people. But such descriptions were not to be found only in Sulawesi. The Sejarah Melayu, most important of all Malay chronicles, claims that kings are the deputies of the Islamic God. In Samudra-Pasai and many other places the sultan was recognized as "God's shadow on Earth." In at least three Malay sultanates, the sultan - often king of a few tens of thousands of people - is referred to as "Caliph" in coins. Even the Quran was dragged in to make the king look as great as possible. If you read Quran 2:30 with context it's pretty clear that God is putting Adam on earth as His successor, but one Malay book of law interprets this as God making the king the successor of God.12
So these political benefits helped make Islamization a sweet deal for a Southeast Asian king. How was this possible? My understanding is that a good deal has to do with Sufism. Ibn Arabi (1165-1240), the "greatest of all Muslim philosophers" according to the Stanford Encyclopedia of Philosophy, advocated the ideal of the "Perfect Man" who has reached spiritual perfection and become one with God. Stanford explains this much better than I could here. Arabi's philosophy was further developed by a certain al-Jili, who summed things up in an essay titled "The Perfect Man":
God created the angel called Spirit from His own light, and from him He created the world and made him His organ of vision in the world. [...] While God manifests Himself in His attributes to all other created beings, He manifests Himself in His essence to this angel [Spirit] alone. Accordingly, the Spirit is the Pole [qutub] of the present world and the world to come. He does not make himself known to any creature of God but to the Perfect Man. When the saint knows him [that is, becomes the Perfect Man] and truly understands the things which the Spirit teaches him, then he too becomes a Pole around which the entire universe revolves. [Translation from A Reader on Classical Islam, p.349]
This philosophy allowed Southeast Asian rulers to claim that through spiritual purification, they had become the Perfect Man. For example, this Acehnese poem from the 16th century describing the sultan:
Shah alam, raja yang adil
Raja qutub yang sampurna kamil
Wali Allah, sampurna wasil
Raja 'arif, lagi mukammil
--
World ruler, king who is just
Axial king whose perfection is complete
Friend of God with communion complete
Gnostic king, yet most excellent
[My slight reworking of translation in Gibson 2007]
Let's look at this poem for a bit. The second line says the sultan is raja qutub. Qutub is 'pole' or 'axis' in Arabic, and as we have seen, the Perfect Man is likened to a Pole around which the world revolves. Next, note the use of the word kamil, an Arabic loanword; 'Perfect Man' in Arabic is *al-insan al-*kamil. The third line says that the sultan is a friend of God, i.e. an Islamic saint, and that he is one with the Divine as a Perfect Man should be. The word wasil is also Arabic and has Sufi connotations of being an intermediary between God and the mortal world, not unlike the Perfect Man. Finally, the sultan is a "gnostic king" just like the Perfect Man who "truly understands the things which the Spirit teaches him." In other words, the world revolves around the holy Sultan of Aceh. And as seen, there were a dozen Perfect Men in the Malay world alone.13
Another way Islam helped strengthen royal authority was by association with the three greatest empires of the Indian Ocean region, the Ottomans in Turkey, the Safavids in Iran, and the Mughals in India. The Ottomans (the Kingdom of Rome, as it was commonly known in Southeast Asia) and the Mediterranean past seem to have been particularly popular sources of legitimization, since most Malay dynasties trace their origins to Alexander the Great who was mistakenly believed to have been the King of Rome. In Java a tradition developed that the Javanese were actually the descendants of Romans. But IMO the most interesting way of asserting legitimacy by using foreign powers is found in Aceh, where the Ottomans are portrayed as an equal rather than a revered source of civilization. According to one Acehnese chronicle, the Ottoman sultan himself proclaims before his entire court that just as Alexander the Great and the Biblical Solomon were the two greatest rulers of the past, he himself, as ruler in the West, and the sultan of Aceh, as ruler in the East, are the two greatest kings of the present day. The Arabs, Persians, and Indians present in Constantinople spread the news in their own countries, so that Aceh's glory is spread across the entire West. What better way of evoking Acehnese grandeur than having the most powerful empire in the known world recognize it?14
Islam helped strengthen royal authority in other ways, like introducing Persianate court culture and male primogeniture or allowing a minor lord to make himself look different from his non-Muslim neighbors and overlords.4 This was especially effective because the pre-Islamic ways of making the king look AMAZING and POWERFUL still existed. In Java, successive kings have had a close relationship with the Goddess of the Southern Ocean (also known as “Nyai Roro Kidul” in Sundanese):
whose supernatural powers wax and wane with the moon.15 One 18th-century Javanese history even says in a positive way that the first Sultan of Yogyakarta "looked like Vishnu."16 In South Sulawesi, as I discuss here, the notion that rulers should serve the people and that the nobility had "white blood" reflective of their supernatural origins was safe and sound in the nineteenth century. Many Malay kings continued to be shamans. And of course, pre-Islamic political terminology was still in use, be it raja in the Malay world or karaeng or arung in South Sulawesi. And all these could be justified on Islamic grounds, e.g. the Acehnese interpretation of the Sanskrit word raja, which as it turns out doesn't actually come from Sanskrit but is an Arabic abbreviation. In the Arabic-derived Malay alphabet raja is written راج . The first letter, د (the 'r' sound), stands for رَحْمَة ﷲ (rahmat allah, 'God's mercy'). The second letter, ا (the 'a' sound), stands for خَلِيفَة (khalifah, 'Caliph'). The last letter, ج (the 'j' sound), stands for جمال (jamal, 'beauty'). So the sultan of Aceh is an Caliph gifted with God's beauty and mercy. Humble.17
Genuine piety
People always discuss economics and politics as possible reasons Islam caught on among the ruling elite. But people aren't Machiavellian machines, especially when it comes to something like religion. There must have been rulers who genuinely found happiness and spiritual contentment in Islam. For an example, let's discuss Karaeng Matoaya, the de facto ruler of Gowa-Talloq, the most powerful kingdom (kinda, it was actually a confederation of two kingdoms, Gowa and Talloq) in South Sulawesi.18
Karaeng Matoaya is described in the Talloq Chronicle as "a wise person." Take into account that this isn't just generic praise. The Chronicle is frank about the personalities of different rulers - even the most recent king to be described in the Chronicle is said to have been "not praised as a knowledgeable person, not praised as an honest person." European sources also report that Karaeng Matoaya "is the most respected there [...] He demonstrated that he is gifted with intelligence and understanding through various discourses which they [the nobles] had with him, in which he frequently astonished them."
So might a "wise person" like Matoaya have had philosophical inclinations? It seems so. An 18th-century chronicle describes Matoaya becoming the student of the wise and old Arung Matoa (elected king) of Wajoq. This is what he asks the Arung Matoa just before the old king's death:
[Karaeng Matoaya] said, "You are very ill, father. Do me the favor of telling me how many gods there are."
The Arung Matoa said, "There is only one God, but there are many emissaries of God."
The Karaeng asked, "Does this God have no mother and no father?"
The Arung Matoa said, "Just for that reason is he called the one God, that he has no mother and no father."19
So it's not much of a surprise that when he converted to Islam, he seems to have had genuine spirituality in mind. To quote the Talloq Chronicle:20
[Karaeng Matoaya was] proficient in writing Arabic.
He often read holy books, never neglected [prayer] times once he became Muslim until his death, except when his foot swelled and he was given alcohol by an English physician. For eighteen nights he did not pray. He often performed optional prayers, such as rawatib, witr, duha, tasbih, and tahajjud.
Said I Loqmoq ri Paotereka [one of his wives], "At the least he did two rakat, at the most ten rakat. [A rakat is a unit of Islamic prayers, two are obligatory] On Friday nights he did the tasbih prayers. During Ramadan each night he gave out alms of gold, alms of water buffalo, alms of rice annually. He did many good works and also prayed often."
The Karaeng of Ujung Pandang said, "He studied many works on Arabic morphology, taking lessons with khatib [preacher] Intang and Manawar the Indian."
But his newfound religiousness didn't come with the violent intolerance sometimes found in new converts. We've already mentioned how Karaeng Matoaya successfully converted his subjects "by the means of tenderness." This tolerance extended to some degree towards Christianity; although conversion to Christianity was not permitted, an Englishman still noted that Matoaya was "very affable and true harted towards Christians." And even when he conquered neighboring kingdoms that refused to accept Islam, the Talloq Chronicle says (and the chronicles of the conquered kingdoms agree):
Conquering the Bugis of the Tellumpocco [a confederacy that refused Islam], he did not trample them and also did not take saqbu katti, did not take raqba bate. They were not taken. [...] Karaeng Matoaya said to me, "At my conquest of the Tellumpocco, not a branch did I break. A sum of three hundred katti [240 kg/530 lbs] of my own gold did I present, did I distribute."
Saqbu katti and raqba bate are indemnities that the defeated kingdom had to pay. The fact that they were not taken, that the victorious armies did not plunder ("trample") the defeated, and that the winners paid money to the losers shows extreme leniency on the part of Matoaya. It's not too much of a stretch to believe that the newly converted Karaeng Matoaya believed that while Islam was worth spreading by the sword, in the end it was a religion of mercy and compassion. When Karaeng Matoaya died on October 1, 1636, he was given the posthumous name of "Tumamenang ri Agamana" - "He who passed away in his faith."
So the evidence suggests Karaeng Matoaya was a pious Muslim who would likely have been quite offended if we said that Southeast Asian rulers converted to Islam for practical reasons only. And it was this piety that kicked off South Sulawesi's marriage with Islam. There must have been dozens more like him. We shouldn't ignore individual agency - piety, love,21 jealousy - in elite conversion.22
But was being a Caliph and a Perfect Man really that better than being Vishnu incarnate and a living Bodhisattva? Hinduism and Buddhism confer many of the same political advantages, so why Islam? Well, there are two things going on. First, let's look at the timing. In Indicized areas of the Archipelago, adopting Islam seems associated with the collapse of major Hindu-Buddhist empires. Samudra-Pasai converted in the late 13th century, when the Hindu Chola empire in south India was collapsing. Melaka's Muslim rulers were themselves descended from refugees who fled the fall of the Hindu-Buddhist empire of Srivijaya. As mentioned, Islam in Java is associated with the decline and fall of Majapahit. So collapse of these once mighty empires that had relied on Buddha and Brahma might have weakened the appeal of Indian religions. Similarly, in mainland Southeast Asia, the decline of the primarily Hindu Khmer empire involved both a political change (Khmers were replaced by Thais) and a religious change (Hinduism was replaced by Theravada Buddhism).23 This might be one reason why Bali is still Hindu. Here, the collapse of Majapahit results in the rise of the powerful Hindu Kingdom of Gèlgèl under King Dalem Baturènggong. Baturènggong's successful reign may have allowed Hinduism to not be discredited in Bali as it was in most of Java.24
In some other parts of Southeast Asia there was no Brahma and no Buddha in the first place. The influence of Hinduism and Buddhism were limited or nonexistent east of Bali.25 So before the arrival of the Portuguese, Islam was the only food on the menu for many Southeast Asian rulers wanting to strengthen their authority.
Finally, I should note that there isn't always a correlation between the coming of Islam and stronger monarchies in the Austronesian world. There were many Muslim kingdoms where the rulers had mainly symbolic power (e.g. Minangkabau). There were also many kingdoms that didn't adopt any world religion and yet had some of the most powerful monarchies in world history (e.g. Ancient Hawai'i). So while there was a tendency for Islam to give kings more power, it was never a hard and fast rule.
II. Why did the people convert?
How fast was popular conversion?
We should distinguish elite and popular Islamization. We can't apply the usual gauges of Islamization like 'let's check how many people have Muslim names' in Southeast Asia because a lot of Muslims didn't actually have Muslim names. So we just have archaeology and a number of local and non-local texts. And what evidence we do have is mixed.
There is much evidence that supports a slow, gradual process. In Java a Dutch report from 1596 suggests that the interior was predominantly non-Muslim.26 As mentioned, the synthesis of Javanese tradition and Islam may not have picked up pace until the 1630s. Palembang (in South Sumatra) has had Muslim rulers since the early 16th century, but local narratives suggest that Islam was not firmly established until the reign of Sultan 'Abd al-Rahman from 1662 to 1706.27 In South Sulawesi, archaeologists have discovered what appears to be the grave of a seventeenth-century noble who was cremated and buried with grave goods, both against Islamic funerary practice and suggesting the persistence of pre-Islamic norms even among the aristocracy a few decades after conversion.28
On the other hand, there's evidence for quick conversion too. Nicolas Gervaise's account of South Sulawesi shows that society there had a strongly Islamic cast just eight decades after Karaeng Matoaya's conversion. Similarly, archaeologists have uncovered less earthenware shards in South Sulawesi after around 1620 despite a rapid increase in both population and wealth, suggesting that Islamic funerals were being held even among peasants just a few decades after royal conversion (archaeology tends to focus on cemeteries, and Muslims wouldn't need to bury pots with the dead).29 And sure, in 1596 most of Java wasn't Muslim. But arguably, that doesn't mean much because the heartland of the Mataram kingdom itself (which unified Java in the 17th century) is said to not have had a Muslim ruler until 1576.30 So a synthesis between Islam and Javanese high culture happened just two generations after the first Muslim king, which is impressive considering there are places that remain non-Muslim despite having been ruled by Muslims for almost a thousand years.
I would say that the adoption of Islamic norms (e.g. not eating pork, which isn't equivalent to the adoption of Islamic thought per se) in Southeast Asia was gradual process on a human level, but a fast event in relative terms.
But there's a lot of caveats to this. First, let's think about the concept of 'conversion' to Islam. Did Southeast Asians really convert to Islam? Or were they doing something else?
Conversion vs Adhesion
I don't pretend to be an expert on religious studies generally. So instead of me talking about something I really don't know much about, I'll just quote The Oxford Handbook of Religious Conversion, p.5 and p.28 (/u/yodatsracist might know more about this):
Arthur Darby Nock's book Conversion (1933) is the second most influential book on conversion. Conversion, for Nock, is a deliberate and definitive break with past religious beliefs and practices. Nock rejected any religious change that was less definitive, which he referred to as merely "adhesion." Nock asserts: "By conversion we mean the reorientation of the soul of an individual, his deliberate turning from indifference or from an earlier form of piety to another, a turning which implies a consciousness that a great change is involved, that the old was wrong and the new is right."
[...]
Adhesion is where there is "no definite crossing of religious frontiers"; it is "having one foot on each side" of a cultural fence because a person or group accepts "new worships as useful supplements and not as substitutes."
Part of the reason the initial expansion of Islam in Southeast Asia was so rapid was because it was (probably) almost entirely 'adhesion' rather than 'conversion.'31 Once the ruler converted, in many places the people would follow him fairly quickly in the initial adoption of the outer trappings of Islam such as not eating pork, destroying idols, circumcising, and wearing less exposing dress. In 1607 the Dutch reported that in the largely animist city of Makassar in South Sulawesi,
"Pigs abound there," though already their numbers are starting to diminish since Karaeng Matoaya converted to Islam two years ago.
"The men carry usually one, two, or more balls in their penis." They are made of "ivory or solid fishbone." This practice is also dying out after Karaeng Matoaya converted to Islam.
"The female slaves whom one sees carrying water in the back streets have their upper body with the breasts completely naked."
"When they wash they stand mother-naked, the men as well as women."
Just forty years later, there are "no hogs at all because the natives, who are Mohammedans, have exterminated them entirely from the country." The women, too, "are entirely covered from head to foot." There are similar cultural changes all across the region.32 So it might look like everyone accepted Islam really quickly. But was this really a conversion in Nock's sense, where there was a "reorientation of the soul of an individual"? There are some local histories that suggest the answer, like this Javanese work talking about the 16th century:33
At that time, many Javanese wished to be taught the religion of the Prophet and to learn supernatural powers and invincibility.
So this is one reason why Southeast Asia was so quick to 'convert.' Popular 'conversion' to Islam was really more of an initial phase of 'adhesion' - people 'converted' as a new way of gaining supernatural support, in addition to everything they'd already been doing. Muslims in Java respected the God of Islam and the Goddess of the Southern Ocean. Before Muslims from South Sulawesi set off on the pilgrimage to Mecca, they would visit the local hermaphrodite shaman for blessings from the spirit world. Islam adhered to society, but did not turn Southeast Asia into a clone of the Middle East.
This isn't to say that Southeast Asians were not 'real' Muslims. Islam gradually became a fundamental part of Indonesian society by 1800. But my point is that Islamization is more than just the split second of 'conversion.' The Islamic confession of faith didn't immediately change how people saw and thought about their world. "The reorientation of the soul" did happen (not everywhere, though), but it happened as a drawn-out process over many generations. Islamization was is a long-term phenomenon through which Islam and Southeast Asian society slowly embrace, as Islam adapts to meet the ever-changing context of Southeast Asia and Southeast Asians adapt to meet the needs of Islam. That's why M. C. Ricklefs, one of the most important historians of Java alive, can talk about "six centuries of Islamization in Java."
Role of state policies
I've asserted a few times above that Islamization was a top-down process without really explaining why. So how important was the state? Could Islam become the majority religion on its own, or was royal support always necessary? Islam was able to spread quite a bit even with non-Muslim kings, especially if the kingdom relied more on trade than farming. I've briefly mentioned above how merchants were likely the first to convert because of the economic benefits of conversion. For example, there was a very large Muslim population in Champa (now Vietnam) by 1595 even though the king was still Hindu - and a lot of this was because Champa was very dependent on maritime trade, since the country is mostly mountain, jungle, and coastline.34
On the other hand, most people in Southeast Asia weren't merchants. Like almost anywhere in the early modern world, most people would have been peasants. AFAIK there's really no evidence that the majority of the peasantry anywhere ever converted to Islam before their ruler did. So while Islam might become a large minority on its own, you need Muslim kings to have the current situation where 93% of Javanese and 99% of Bugis are Muslims.
Islamic law: Did it matter?
Islamic law generally has ways to encourage non-Muslims to convert. Many people in India and elsewhere converted because being Muslim gives you an advantage in the eyes of the village qadi (Muslim judge), for example. Was this also the case in Southeast Asia?
First, just to clarify: shari'ah (as in 'sharia law') was and is venerated throughout the Islamic world, including Southeast Asia. In South Sulawesi, shari'ah is considered one of the five pillars of local society. The Four Stages of Sufism, the first of which is shari'ah, has been well-known across Southeast Asia for centuries. But despite the ramblings of r/the_donald or wherever, shari'ah is much more than just chopping off hands (this is well-explained by /u/yodatsracist here.) A respect for shari'ah doesn't mean you're carrying out all the Islamic law.
So how important was Islamic law? It certainly had some influence. There were qadi, Muslim judges, in many bigger Malay kingdoms ever since Melaka during the reign of Sultan Mansur (r. 1456-1477). In South Sulawesi too, divorce, marriage, and inheritance proceedings might be dealt with by folks at the mosque. In 19th-century Palembang, Sumatra, there was an "ecclesiastical court" in charge of family law. Major Shafi'i (Shafi'i is the school of Islamic law that Southeast Asians follow) books of law were also translated from Arabic into Malay.
In general, when Islamic law is applied, there's a strong tendency to ignore what the Qu'ran has to say on physical punishments.35 Many Southeast Asians seem to have been horrified by punishments like "amputate their hands in recompense for what they committed" (Quran 5:38), and the law codes of most kingdoms just say thieves and even murderers will be fined. But thankfully, people are much more likely to get into a divorce proceeding or ownership disputes than murder and robbery. Many kingdoms used Islamic law for family or commercial law, which means that Muslims were privileged over non-Muslims in many of the court cases that actually affected daily life. So in some places, especially in the cosmopolitan cities of the west like Melaka, Aceh, and Banten, Islamic courts probably encouraged people to convert.
But Islamic law didn't matter everywhere. A lot of people who had grandiose Arabic titles were actually just doing whatever they'd been doing before Islam. One example is from Maluku, where the sultan of Ternate appointed hukum (from Arabic hakim, 'judge') to rule on court cases. But these hukum were just nobles and royal relatives who had paid money to the sultan to get this title and might not even know how to read, never mind know anything about Islamic law. These hukum made judgments based on "reason and custom," not Islamic law. For important cases, they convened a meeting of local elders.36 In some places the power of custom was so strong that inheritance passed from mother to daughter, outright defying Islam's most basic inheritance laws. In Java, too, an orthodox Muslim writer criticizes an apparently common practice:37
It is unbelief when people involved in a lawsuit and invited to settle the dispute according to the Law of Islam, refuse to do so and insist on taking it to an infidel judge.
Even in places where Islamic law was partly applied, like Melaka, the chief justice often had a non-Islamic title and judges were ultimately told to make decisions based on "the [traditional] law of the city or the villages" that they were in charge of.
To conclude: Islamic law mattered, but only in some places and only to a degree. Islam wasn't spread by foreign conquerors, meaning that pre-Islamic legal traditions continued to hold great influence and weaken the direct impact of the shari'ah. While I don't doubt some Southeast Asians converted to gain an advantage before the law, it was probably a relatively minor reason for conversion at least compared to more shari'ah-minded countries like the Ottomans.38
Popular religion before Islam
Alan Strathern, a historian of Sri Lanka, has argued that there's a "Transcendentalist Intransigence" (JSTOR article) when it comes to conversion. The article is worth reading, but what Strathern is saying is pretty simple:
A ruler [or anyone, really] is less likely to convert to a new religion if:
he follows an organized religion like Christianity, Islam, Hinduism, and Buddhism39
this organized religion is a fundamental part of the society where he lives
This might be why India, ruled by the British for almost 200 years, is 98% non-Christian. Even most majority-Muslim areas of India were never really Hindu in the first place, so in the end, most Hindu communities have stuck with their religion despite some 700 years of non-Hindu rule.
But Indonesia did have organized religions, Hinduism and Buddhism! But while that satisfies criterion 1, were Hinduism and Buddhism really a fundamental part of pre-Islamic Indonesian society? Would your average Indonesian peasant been a 'Hindu' or a 'Buddhist'? The little evidence we have suggests no. In all of Indonesia, Hinduism and Buddhism had the greatest impact in Java. But even in Java in the 14th century during the Majapahit empire, which was the height of Hindu Javanese civilization,40
primeval native Javanese religious speculation and popular belief in fact still dominated life of the majority of Javanese, both high-born and common, at court and in the country. [...] Probably among the gentry and the common countrymen in the rural districts education in the Indian sense was superficial.
Similarly, while the Indian caste system was known in Java, it "seems to have had no validity in actual life."41 Hindu dietary laws also had little impact on what commoners ate. One 14th-century Javanese poem contrasts the Hindu rules for food with what people actually ate (Nagarakertagama 89:5 and 90:1)42:
Dogs, tortoises, worms, mice are forbidden [to eat under Hindu law], on the other hand frogs are mean, very.
[...]
Frogs, worms, tortoises, mice, dogs
How many there are who like those [meats]! They are flooded with them, so they appear to be well-pleased.
This isn't to say that the average Javanese had no knowledge of Indian religious concepts. They most likely knew at least little, thanks to things like networks of ascetics and ashram monasteries or puppet plays about Hindu heroes. But Indian religions weren't strong enough to fundamentally influence the Javanese lifestyle, as Islam was to do. So, to quote one anthropologist, "clearly there was no Hinduism in Java, only a Javanese religion that drew on Indian religious praxis and mixed it with local ones."43
Outside Java, people were even less attached to Indian religions. For example, one Sumatran king (Adityavarman) encouraged Buddhism in the mid-14th century. But once he dies, "nothing more is heard of Buddhism." Adityavarman's "demonic form of Buddhism" involving "rites of human sacrifice, the drinking of blood and the rattling of human bones in ecstatic dances" might actually have scared any potential converts out of the religion!44 And in many places in Indonesia there just weren't any Buddhism and Hinduism in the first place.
So when most Southeast Asians converted to Islam, they weren't converting from Hinduism to Islam, which we know from India didn't happen that much. The vast majority of Indonesians were converting from animism to Islam, which we know can happen much more easily. This animist heritage, more so than Indian religions, would be what shaped initial perceptions of Islam in Southeast Asia.
Role of Sufi missionaries
In 1961, a young historian named A. H. Jones wrote an influential essay titled "Sufism as a Category in Indonesian Literature and History." There, he argued that there was "a single factor, the appeal of Sufism," which explained why so many Southeast Asians became Muslim. These Sufis were appealing, says Jones, because they were associated with trade, because their basic philosophy was broadly familiar to Southeast Asians, because they were seen as powerful wizards, and perhaps most importantly, because they were willing to "preserve continuity with the past." Sufism has featured prominently in accounts of Southeast Asian Islamization ever since.
A generation later in 1993, an old historian, also named A. H. Jones, wrote an essay titled "Islamization in Southeast Asia : Reflections and Reconsiderations with Special Reference to the Role of Sufism." Jones indeed reflected and reconsidered the conclusions he had made in 1961. He still believed Sufism to be important. But it was certainly not the only factor in the spread of Islam. He writes:
Is it not likely that religious change was gradual, and came about after a long process of association between local peoples and Muslims, beginning with curiosity, followed by a perception of self-interest leading eventually to attachment to and finally entry to that religious community, rather than a response on an individual basis to the preaching of a message? In the light of such considerations, my idea of the primacy of the mystical dimension of Islam in the Islamization of Southeast Asia needs re-consideration, and along with it a number of tacit assumptions as to the nature of Sufism and its relation to Islam more generally that lay behind it.
The fact that one scholar's views could evolve this way shows well the disputed role of Sufism in Southeast Asia's Islamization. Some historians believe that Sufism was critical to conversion. Other historians argue the complete opposite. "Far from being a mechanism of conversion," says historian Michael Laffan, "Sufism was formally restricted to the regal elite."45 Then there are historians who agree that Sufism was important for some places like Java and South Sulawesi, but point out that a lack of evidence from other regions means that we shouldn't extrapolate from Java or Sulawesi to say that all of Indonesia was converted by Sufis.46 I personally tend towards a more positive view of the importance of Sufism, though I also agree that for many places there's no evidence for early Sufi involvement either way. So keep that in mind as you read what follows.
Islam as Magic
Like the Javanese who learned Islam to turn invincible, many Southeast Asians would have first seen Islam as a new way to acquire supernatural powers. 'Religion' in animist Southeast Asia was often a matter of finding the best way possible to gain superhuman support for yourself. As one Christian missionary described of animists in Borneo,
Their interest in religion is a matter of tactics. The more a man knows about ritual, the more he can do for his own and for his family's welfare. A person's wealth is proof of his theological knowledge. They are continually changing their adherence from one set of spirits to another. If they make the right moves they will die rich and buy their way into Heaven with huge animal sacrifices.
Islam was seen a set of rituals and beliefs that was particularly efficient at gathering supernatural power. You can see this in many conversion myths. A Sufi master arrives to convert the king of Kutai in eastern Borneo. The king offers to convert if the Sufi can best him in a magic battle. The king turns invisible, but the Sufi walks over and stands behind the king, proving that he can see through the magic. The king then utters a magic spell to create an enormous fire, but the Sufi prays twice to summon a huge rainstorm that puts out the fire and then floods all of Kutai. Finally the Sufi summons his monster swordfish and the king finally decides to convert. Islam being linked in the popular imagination with such phenomenal cosmic powers superior even to the authority of the king, a Kutainese might have thought: wouldn't following these Muslim rituals improve my lot in life at least just a little?
The ties between Islam and magic are made more explicit in this incantation used by 18th-century Malay sorcerers:
I sit beneath the Throne of God;
Muhammad my shelter is beside me,
Gabriel on my right, Michael on my left,
All the company of Angels following me.
Only if God suffer harm,
Can I suffer harm:
Only if His Prophet suffer harm,
Can I suffer harm.
Why this association with Islam and magic? As the Kutai story implies, Sufis should take some credit for Islam being associated with powerful magic. Many Sufis and their adherents sincerely believed that supernatural power could be acquired through training, while Sufism absorbed pre-Islamic forms of magic with relative ease.
Kings, however, may have been even more important in the process of Islam becoming accepted as magically superior to other rituals. In much of Southeast Asia, rulers were believed to be a source of supernatural power. This was true before Islam, and this was generally true after Islam. As late as the 1820s the Muslim king of Pagaruyung in Sumatra was said to be capable of calling down epidemics or ruining harvests if a vassal was disobedient.47 But what happens when that king is Muslim? The most logical conclusion: since the king is spiritually and magically powerful, and since the king follows Islam, Islam must also be spiritually and magically powerful. So why not practice Islam to get all this power?
Evidence for this can be seen in the 18th-century Raja Ampat Islands, an archipelago next to New Guinea. The Raja Ampat Islanders gradually converted to Islam in that century as it fell under the influence of the Muslim sultanate of Tidore. But why? In 1705, the sultan of Tidore sent a letter to his subjects in the Raja Ampats. After the Tidorese envoy read the letter out loud during a meeting with the local chiefs, the chiefs solemnly said "Amen." Yep, the word "amen" that you say after a prayer. To the islanders, the Islamic prayer and the words of the sultan were comparable in sacredness.
For context, let's see what the Raja Ampat chiefs did when they visited the palace of Tidore to pay tribute. The chiefs crawled all over the palace so that their body could absorb not only all the dust on the floors, but also all the supernatural power of the sultan that had accumulated in his palace. After they returned, the islanders crowded around the chiefs to touch them because they wanted to share in the sultan's spiritual powers. Anything to do with the sultan was a potential source of magic, from his letters to his envoys to the Muslim clothes he sometimes gifted to the chiefs. Such was the spiritual potency of the sultan of Tidore.
The Raja Ampat Islands were kind of in the middle of nowhere. There weren't any Muslim judges, there weren't any Sufis, and there were few foreign merchants until later in the century. But people still converted to Islam because the sultan was holy, the sultan was a Muslim, and practicing Islam was a way to access the sultan's holiness. The episode with the chiefs saying "amen" to the king's words shows that at this early stage of Islamization, it wasn't Islam itself that was considered sacred; it was the sultan, and Islam was sacred because the sultan was Muslim.48
One final reason for Islam being perceived as particularly potent is the fact that it is, after all, the Religion of the Book. There was a reverence towards writing in many places in Southeast Asia. Historian Barbara Andaya notes that in South Sumatra,49
Texts of various forms were certainly present in villages as well as in courts, but they were regarded as sacred and magical objects, like krises [swords], spears, ancient cloth, [and] bezoar stones. Stored with the regalia or with the community's power-charged palladia (sacral items to which popular belief attributed supernatural protection), they were generally venerated rather than consulted.
Many Southeast Asians would have readily accepted the fact that the Quran was sacred, if only because it was a book. We know that people in 17th-century South Sulawesi sacrificed animals before copying the Quran, perhaps to appease the spirit of the Book. But the Quran held greater spiritual authority than virtually any other written work. First, much of the power of the written word lay in its connection with the moment when the text had first been penned:50
Manuscripts were more than mere histories. They were the very past made present when the words they recorded were respoken, and such a function inspired awe and presumed great supernatural power. As objects, manuscripts offered a connection to a moment of origins in which were unleashed generative powers whose traces still had effects in the world.
The Quran transported Southeast Asians to the origins of Islam and ultimately to God. It was a sort of talisman that people could use to access the spiritual powers of the ancient prophets and of God Himself. Few works in Southeast Asia could claim such powerful links.
The Quran was also written in Arabic, an arcane language virtually nobody knew. The use of this mysterious ritual tongue allowed the Quran to be conceived as even more powerful, "precisely because Arabic was not understood; the whole point of a spiritual ritual in an uncomprehended language is that it manifests power, and implies a deliberately nonrationalist mode of cognition."51
As a mysterious, unreadable book that radiated spiritual force, the Quran was the perfect symbol of the supernatural authority of Islam. It may well have convinced more than a few doubtful Southeast Asians that Islam did have great spiritual power. At least, that's what one anecdote collected by a Britishman says:52
[A Muslim Malay said to an animist,] "You pay a veneration to the tombs of your ancestors; what foundation have you for supposing that your dead ancestors can lend you assistance?" "It may be true; answered the other; but what foundation have you, for expecting assistance from Allah and Mahomet?" Are you not aware, replied the Malay, that it is written in a Book? Have you not heard of the Koraan?" [sic] The [animist], with conscious inferiority, submitted to the force of this argument.
Islam in a Changing World
The Early Modern era in Southeast Asia was an age of turbulence and change. Agriculture expanded. The volume of trade was greater than it had ever been. New cities emerged, rose to unprecedented heights, then collapsed to rubble. Populations quintupled, then shrank by 93%. The first Europeans arrived in the 16th century under the banner of holy war, and slowly over the course of the 17th century, the Dutch East India Company gained hegemony over the Archipelago. Trapped in this unpredictable environment, many Southeast Asians may have seen Islam as the religion that could best cope with change.
Islam and Agricultural Development
Why is Bangladesh Muslim when it's the part of India the furthest away from the Middle East? The consensus is that Islam spread there because it used to be mostly jungle. It was cleared and turned into fertile rice fields during Islamic rule, so becoming Muslim just happened to come with the package of adopting agricultural civilization. Were things similar in Southeast Asia?
Here's a summary of one legend from Central Java about how Islam arrived on the local level:53
One day, a kyai (religious expert) is ordered by his teacher to go and spread Islam. The kyai arrives at an ancient forest straddling a river and begins to pray. Deep in his prayers, he hears God's revelation that the forest should be cleared north of the river so that a mosque may be built. But there is a problem. The forest is sacred to Durga, a Hindu goddess, and is angker (haunted) by powerful gods and spirits. The kyai and his followers miraculously overcome the spirits' resistance through their Muslim piety and found a Muslim community, complete with a mosque, over the ruins of a sacred forest.
There are similar stories elsewhere in Java. In 1773, the respected Muslim scholar Muhammad Arshad al-Banjari returned from Mecca to his homeland in Banjarmasin, a Javanized kingdom in southern Borneo. Pretty much the first thing he did was to transform "a large plot of wasteland outside the capital" into an Islamic center supported by "productive rice fields and vegetable gardens."54 Pilgrims returning from Mecca were the pioneers of wet rice agriculture in West Java, too.55 At least in the Javanese world, Islam was tied to the act of mbabad, 'to clear wilderness.'
In some places, Muslim leaders created new agricultural communities in the midst of jungle by reducing many of the sacred forests that had been revered by animists. People had to adapt to a new life in settlements that could exist solely because the power of Islam had been displayed over the sanctity of the wild. Accepting Islam was seen as part and parcel of accepting a life in these new rural societies.
However, we wouldn't have a full understanding of either agricultural development or Islamization in Southeast Asia if we thought things were the same as in Bangladesh, where most agricultural expansion was led by Muslim preachers and Islam spread mainly due to agriculture. Even in Java, most land reclamation was led not by kyai but by the sikep, or peasant landlords.56 In other areas, the most rapid agricultural development happened before Islam. More importantly, Southeast Asia was more dependent on foreign commerce than Bangladesh would ever be. How did commercial development square with Islam?
Islam and Commercial Development
Let's return to this chart of estimated European spice imports from Southeast Asia:
The volume of exported spices rose by 10 times in the 15th century, not even including pepper, and rose by 22 times until the 1620s. There were similar surges of demand for Southeast Asian goods in China, which was undergoing its own commercial revolution.
This immense demand allowed Indonesian cities to reach heights that had never been seen before. In just a century, Melaka in the Malay Peninsula grew from a small fishing village to a city that the Portuguese believed to have "no equal in the world." In 1500, Makassar in South Sulawesi was a town with maybe a few thousand people; in 1640, it was a sprawling metropolis with as many as 190,000 inhabitants. The first cities in Java developed around this time, with Banten in West Java having possibly as many as 220,000 people.57 With the majority of the population in most Malay kingdoms probably living in cities, Early Modern Southeast Asia may have been one of the most urbanized regions in the world.58
In every part of Archipelagic Southeast Asia59, genuine urbanization first arrived in the Early Modern era with the coming of Islam, and urban and cosmopolitan culture was often perceived as inherently Muslim. This is why laws dealing with urban life are the most influenced by shari'ah and why the Portuguese reported that people in Maluku considered Javanese traders to have given them not only Islam, but also 'high culture' in general like money and music:
They [the Malukans] say that they took these [royal] titles from the Javanese who made them Muslims and introduced coinage into their country, as well as the gong, the shawm, ivory, the kris [sword], and the law, and all the other good things they have.
There is archaeological evidence that rural populations around Makassar declined just as Makassar was entering its era of greatest prosperity.60 These mega-cities attracted thousands of people from the countryside, who would have been exposed to a way of life entirely different from what they had always known. Cosmopolitan civilization was associated with Islam, so following the religion would have been seen as integral to adopting to the culture of your new home. And there were of course no familiar spirits in the cities that you could ask for guidance or assistance. But Islam is the unchanging Word of God and is true everywhere. Historian Anthony Reid also argues that Islam provided "an Islamic 'Protestant ethic'" that encouraged urbanites who wanted to make money; one Javanese book of ethics claims that Muslims should sleep little and work hard, not caring whether people call them stingy or not.61
In these diverse ways, people in the cities would have followed Islam because it was simply the spiritual system that best suited urban life. Even if you didn't live in the city, "since the port cities were also the dominant political and cultural centers of the period, their Islamic character eventually influenced all who lived within their economic orbit." Islam spread in Southeast Asia partly because it was seen as the religion of the city.
Islam as part of life (and a conclusion of sorts)
The Minangkabau people of West Sumatra have been described as matrilineal, even matriarchal. The rhythm of life here was dictated by an extended lineage made up of several generations of women with their husbands and prepubescent children, who all lived together in magnificent longhouses. The longhouse, like everything else, was passed down the female line. Even the personal property of a man would eventually be absorbed into his wife's family's collective holdings once he died. Sons and brothers left the longhouse when they reached puberty and spent many years seeking their fortunes abroad (this voluntary migration is called merantau) before returning to Minangkabau country to marry.
This type of society seems fundamentally opposed to Islamic family norms, but most Minangkabau were Muslim by 1750. Islam had found a way. When boys left the longhouse, they first went to the surau - a kind of 'men's house' for the family where adolescents lived before leaving on merantau. With Islam, the surau gradually lost its connections to a specific family as they morphed into Islamic boarding schools associated with one Sufi brotherhood or another. The surau of particularly famous Sufis attracted a thousand teenagers or more, including many who had come from distant longhouses.
If the purpose of the surau was to prepare boys for their merantau and turn them into men, Islam had made it much more effective. Young teens now traveled long distances to faraway surau to meet hundreds of people their age, none of whom they had ever seen before. The surau was where boys learned how to make new friends and shared information (like details on having sex!) with their peers. Here they were trained in Islam, a religion that would be useful anywhere abroad, and steeled against potentially devastating temptations like opium and prostitutes. But of course, most Minangkabau teenagers probably didn't go to the surau because they were convinced of the virtues of education. They went because it was what everyone their age did. By entering and perfecting a niche in the Minangkabau way of life, Islam had become part of the life cycle of Minangkabau men.62
Back home in the longhouse, each matrilineal clan (clans are made up of multiple related longhouse families) maintained an imam who dealt with religious matters like divorce proceedings. But more importantly, the imam "was present at births, deaths, and family ceremonies such as the first bathing of a newborn child, house-moving, the start of a [merantau] journey, and so on" - in essence, all the major ceremonies of life.63 Similarly, one manuscript from South Sulawesi expects clerics to make a living by getting paid for things like officiating at marriages or attending funerals.64 Throughout Southeast Asia, the influence of Islam was felt to varying degrees in all major life-cycle ceremonies. From birth to death, the religion was part of the rhythm of life.
Many Indonesian peoples have developed elaborate creation stories that trace the origins of the fundamental elements of their own society. The rise of Islam as an essential element of life meant that this new religion had to be somehow fit in this existing cosmology. Here's how the Bugis of South Sulawesi do it:65
One day, when all their adventures are over, all the gods and heroes of the Upperworld and Underworld alike meet in the kingdom of Luwuq. Déwata Sisiné, the Creator of the World, makes a surprising revelation to the divine assembly. It has been determined that the the Upperworld and Underworld must be emptied of the gods. From now on, only angels and jinns shall be allowed to live there. The gods of the Upperworld depart for the east, to the land of the sunrise; the gods of the Underworld depart for the west, to the land of the sunset. Only Déwata Sisiné remains. That is why people today worship only Déwata Sisiné and have forgotten the old gods. The latter have left this world.
No - there was one other god who remained. Before his departure, Sawérigading, king of the Underworld and greatest of all heroes, proclaims to the Bugis that he shall return. He shall be reborn in a pure womb in the land of the sunset. He will have a different name and the Bugis will not recognize him at first. But when Sawérigading returns, the Bugis must make sure to accept his teachings.
The ancient creator god Déwata Sisiné is the Islamic God, while the hero Sawérigading is of course the Prophet Muhammad. Islam had never been a foreign religion, said the Bugis. It had been with them since the very beginnings of their world. In these ways Islam became an integral part of the life and cosmology of Minangkabau, Bugis, and other Indonesian peoples - all while at harmony with the existing fabric of life.
From time to time, there were men and women who sought to tear up this harmony and replace it with a 'purer' Islamic lifestyle. One of these men was the Tuanku Imam Bonjol, who led a Wahhabi-influenced fundamentalist revolution in Minangkabau country. Longhouses were burnt, the upholders of traditional society were murdered, and women were forced to wear the burqa. But the Imam began to have doubts. One day, he asked: "There are yet many laws of the Quran that we have overlooked. What do you think about this?"
In 1832, news arrived in Minangkabau country that the Ottomans had conquered the Wahhabis and that the First Saudi State had been obliterated. The Tuanku Imam had a moment of epiphany. Militant Wahhabi-style fundamentalism was invalid. All the depredations that the Imam had committed against adat, or Minangkabau tradition, were therefore also invalid. From the Tuanku Imam's memoirs:
So all the plunder and spoils were returned to their owners. And Friday, when everyone had arrived at the mosque, and they had yet to start their prayers then the Tuanku Imam, before all the judges, restored things to as they had been. "I speak to all the adat [traditional] leaders and all the nobles in this state. And although more enemies may come from all directions rather than fighting them you adat leaders and I will live in mutual respect and peace and no longer will I meddle in the lives of the adat leaders in the state of Alahan Panjang. And so I restore all that is bad and good." [...] And if there was a problem with adat it would be brought to the adat leaders. And if there was a problem with Islamic law it would be brought to the four Islamic authorities.
When the Tuanku Imam Bonjol fought again in 1833, he did so as a leader of all Minangkabau, reformists and traditionalists alike. The zealous radical had learned to accept the importance of tradition.66
Islam had first prevailed as magic, then as anti-colonial resistance. But ultimately, it prevailed because it could coexist with what had been there before without marginalizing itself. The fact that even people like the Tuanku Imam Bonjol could find an important role for both Islam and tradition was the cause and symptom of Islam's success in such a faraway land. Some say the Tuanku Imam was the first to make the proverb I quoted at the beginning:
Adat basandi syarak; syarak basandi adat.
Tradition is based on religion; religion is based on tradition.
This follows Azyumardi Azra's Islam in the Indonesian World: An Account of Institutional Formation, p. 7-10. Azra is one of the few historians of Indonesia who work extensively with Arabic sources.
For Raffles's Orientalism, Rethinking Raffles: A Study of Stamford Raffles' Discourse on Religions Amongst Malays by Syed M. K. Aljunied is often cited. There is some dispute over whether Clifford Geertz, an anthropologist who in 1960 wrote an influential book titled The Religion of Java, was part of this tradition. Geertz has influenced many of the current senior generation of SEAnists like M. C. Ricklefs, but there's a lot of SEAnists who are strongly opposed to him: Mark Woodward argues that Geertz's work "is best understood as [...] a combination of Orientalist and colonial depictions of Islam, Java, and Indonesia" (Java, Indonesia, and Islam p. 59) and Jeffrey Hadler in Muslims and Matriarchs believes "there is a line of intellectual descent running from Raffles [...] on to Clifford Geertz [which is] a tradition of disregarding or demonizing Islam in Indonesia." For more, see Michael Laffan's The Makings of Indonesian Islam: Orientalism and the Narration of a Sufi Past and William R. Roff's "Islam obscured? Some Reflections on Studies of Islam & Society in Southeast Asia."
That user's stated proof for this is that Malukan rulers switched around between Islam, Catholicism, and Protestantism depending on who they were trading with, which is false. Some chiefdoms did 'convert' back and forth, like Manado which went from Islam to Catholicism to Islam to Catholicism to Islam to Protestantism in just a century. But they had to do with political allegiances, not trade. BTW, Manado was of little political relevance. To the best of my knowledge, more important Malukan kingdoms like Tidore and Ternate have never had a king abandon Islam for another religion.
A rather unsatisfactory answer because OP doesn't even talk about Myanmar and Thailand.
The Balinese caste system is said to have been invented by the Javanese priest Nirartha some time after 1537. Per Java in the Fourteenth Century: A Study in Cultural History, vol IV p.260, caste "seems to have had no validity in actual life" in Hindu Java.
For Ottoman imperialism in the Indian Ocean, see Giancarlo Casale's The Ottoman Age of Exploration.
World of Maluku: Eastern Indonesia in the Early Modern Era by Leonard Andaya, p.136.
See Anthony Reid's "The Rise and Fall of Sino-Javanese Shipping" and Geoff Wade's "Southeast Asian Islam and Southern China in the Second Half of the Fourteenth Century."
For Islam in the Philippines, the standard text AFAIK remains Cesar A. Majul's Muslims in the Philippines. I haven't read Majul or anything about the Philippines really, the references to the Philippines here are from general sources. For Malays in Sulawesi, see Heather Sutherland's "The Makassar Malays: Adaptation and Identity" in Contesting Malayness. For trade in Maluku generally, see World of Maluku.
For local sources' views on conversion, see Wyatt and Teeuw's 1970 translation Hikayat Patani: the Story of Patani and William Cummings's 2007 translation A Chain of Kings: The Makassarese Chronicles of Gowa and Talloq.
For this I rely on Michael Charney's PhD thesis, Where Jambudipa and Islamdom Converged: Religious Change and the Emergence of Buddhist communalism in Early Modern Arakan (Fifteenth to Nineteenth Centuries), which is always cited in any discussion of religion in precolonial Arakan. Charney is more-or-less the only living historian who has done extensive work on Arakan and he says he's getting his thesis ready for publication, so get hyped. Also see his article "Crisis and Reformation in a Maritime Kingdom of Southeast Asia: Forces of Instability and Political Disintegration in Western Burma (Arakan), 1603-1701."
All examples from "Islam and the Muslim State" by A. C. Milner in Islam in South-East Asia, p.35-36.
For Perfect Men in Southeast Asia, see "Islam and the Muslim State" by Milner for a general overview. For Aceh, see Islam and State in Sumatra: A Study of Seventeenth-Century Aceh by Amirul Hadi, esp. p.57-65. For South Sulawesi, see Islamic Narrative and Authority in Southeast Asia by Gibson, Chapter I, "The Ruler as Perfect Man in Southeast Asia."
However, use of foreign empires to bolster legitimacy was rare or nonexistent in some areas, so evoking foreign connections was a strategy contingent to the region. For Ottomans and Malays, see The Turkic-Turkish Theme in Traditional Malay Literature: Imagining the Other to Empower the Self by Vladimir Braginsky. There is no study of the cultural importance of Ngrum (Rome) in Java that I know of, but the story of the Roman resettling of Java is recounted in Ricklef's article "Dipanagara's Early Inspirational Experience," p.241-244. For Mughal influence in Aceh, see Denys Lombard's Le Sultanat d'Atjeh au temps d'Iskandar Muda, p.79, 139, 174, 180.
The late sultan of Yogyakarta, Hamengkubuwana IX, was particularly close with the Goddess. Several Indonesian newspapers have reported that the Goddess attended the coronation of his son, the current sultan, in 1989.
Jogjakarta under Sultan Mangkubumi by M. C. Ricklefs, p.81. But to be fair, by this point Vishnu was conceived as the first mythological ruler of Java, descended from Adam and Eve. So it's not necessarily a direct Hindu reference.
See Islam and State in Sumatra, p.57-58 for the Arabic interpretation of raja. See "A Change in the Forest: Myth and History in West Java" by Robert Wessing for an example of a 'shaman sultan.'
So, on sources. Most detailed information about Karaeng Matoaya and his personality comes from South Sulawesi chronicles, and here I cite the Talloq and Wajoq chronicles. Karaeng Matoaya ruled Talloq at the height of its glory, while Wajoq was the closest ally of Gowa-Talloq for much of the 17th century. So these sources are far from neutral (not to say that there ever is a perfectly neutral source, but you get my point). But at least the Talloq Chronicle was written within 15 years (and probably within 11 years) of the death of Matoaya, which reduces the likelihood of later interpolations. The Wajoq chronicles are a different beast, having been entirely rewritten after 1737.
Of course, we could doubt this ever happened. 'One God' is Déwata Sisiné, who is also the deity who creates the universe and all the other déwata (gods) out of the void. Déwata Sisiné would indeed have no mother and no father, and saying that there is only one God who has many emissaries technically fits with both Islam (the Abrahamic God and the Prophets) and Bugis religion (Déwata Sisiné and the other gods). But still, saying there's only one God is a little weird for a non-Muslim to say because the lesser divinities of the pantheon are still recognized as déwata, gods. This chronicle was written at least 130 years after this purported conversation, so we should probably accept the idea that a little too much Islamic theology got in the conversation (assuming it's not fabricated to link Wajoq to Karaeng Matoaya).
Primarily using Cummings's 2007 translation of the KIT 48 copy of the Chronicle, p.89 and 95-96, but the last paragraph is from Noorduyn's "Makassar and the Islamization of Bima," p.315.
Portuguese sources report that the first Muslim ruler of Ternate, the spice island in Maluku, converted for the sake of his Muslim wife.
Reid has a short biography of Karaeng Matoaya in his chapter "A Great Seventeenth Century Indonesian Family: Matoaya and Pattingalloang of Makassar."
This theme of political collapse and division from around 1250, accompanied by major political and cultural changes across Southeast Asia and the world, is eloquently argued in Victor Lieberman's Strange Parallels: Southeast Asia in Global Context.
For Gèlgèl, see Adrian Vickers, Bali: A Paradise Created. The Balinese had no particular hostility towards Islam (they seem to have considered it a potent form of magic) and non-nobles converting to Islam was actually permitted. Nevertheless Bali is very Hindu today, again showing how Islamization was a top-down process.
A number of Buddhist statues have been found in South Sulawesi, and there is a vihara from the fourteenth century. But the statues don't mean much by themselves, since Buddhist statues have been found in Sweden, and so far just the one vihara (which looks Javanese) has been discovered. More importantly, South Sulawesi had no Hindu-Buddhist temple architecture, no knowledge of Indian concepts that went any deeper than a superficial level, and little Indian terminology except for a few Sanskrit loanwords which come from Malay, not directly from India.
"Islamization and Christianization in Southeast Asia: The Critical Phase" by Anthony Reid, p. 155.
To Live As Brothers: Southeast Sumatra in the 17th and 18th Centuries by Barbara Andaya, p. 112.
"A transitional Islamic Bugis cremation in Bulubangi, South Sulawesi: its historical and archaeological context" by Stephen Druce et al.
p.90 in "Makassar Historical Decorated Earthenwares" by F. David Bulbeck, chapter in Earthenware in Southeast Asia
Ricklef’s History of Modern Indonesia since c.1200, p.47
Anthony Reid argues that Southeast Asian Islamization was indeed conversion rather than adhesion in his chapter "Islamization and Christianization in Southeast Asia: The Critical Phase, 1550-1650" in Southeast Asia in the Early Modern Era: Trade, Power, and Belief. So again, note that what I say is far from a universally accepted position, though I would argue that it's the stance held by the majority of scholars.
See Reid's Age of Commerce volume I for these changes. More specifically, p.35 for the rapid abandonment of formerly popular meats like pork, dog, frog, and reptile meat, all forbidden under Islam; p.40 for Islam's failure to get rid of alcohol; p.67-68 for mosque architecture; p.77 for elimination of tattooing; p.81-89 for other changes in attire such as hairstyle, fingernails, and clothes; p.217-235 for literacy and literature (Though I'm not so sure about Reid's assertion that popular literacy was widespread in South Sulawesi and elsewhere before the coming of Islam. Per The Lands West of the Lakes by Druce, p.73, literacy was limited to the white-blooded aristocracy prior to Islam. And while Reid claims literacy declined after Islam, most surviving South Sulawesi texts date from the 18th century, suggesting a rise in literacy or at least book-writing at that time. See Pelras's 1996 The Bugis, p.292-295)
This is the Babad Tanah Jawi (History of the Land of Java), or more specifically, a version of the Babad that dates from the early 19th century. So we can and should doubt how accurately it reflects conditions 300 years ago. But considering that orthodox Islam was more established in 1800 than in 1500, something similar to this did likely happen.
See Pierre-Yves Manguin's "The Introduction of Islam in Campa" if you want to learn more about, err, the introduction of Islam in Champa.
Except in Aceh, where amputations and other forms of physical punishment were so severe that they horrified visitors even from Mughal India. See The World of the Adat Aceh: A Historical Study of the Sultanate of Aceh, PhD thesis by Takeshi Ito, p.152-206. Banten also had amputations during the reign of Sultan Ageng (r. 1651-1683), as did Maguindanao (in the Philippines) some time in the 1700s, but those didn't last.
Andaya, World of Maluku, p.70
An early Javanese code of Muslim ethics, translation by G. W. J. Drewes, p.38
For an overview of law in Early Modern Southeast Asia, see Reid, Age of Commerce vol I, 137-146.
Of course Buddhism is much more diverse than most Abrahamic religions, while Hinduism really isn't one religion at all. But here I mean the variants of these religions officially backed by the state - I'm not sure how Hinduism worked in India, but Theravada Buddhist orthodoxy was strictly enforced by law in Myanmar and Thailand.
The main general source on Majapahit AFAIK is still Java in the Fourteenth Century: A Study in Cultural History by Theodore G. T. Pigeaud, even though it's more than 50 years old (from 1962). I could be wrong and there might be newer general sources, but if there are I haven't seen them. For religion in Majapahit, see Java in the Fourteenth Century volume IV, p.479-494. I specifically quoted p.480-481 and p.487.
For caste see Java in the Fourteenth Century vol. IV, p.260-261.
From Java in the Fourteenth Century vol III, p.106
Durga's Mosque: Cosmology, Conversion and Community in Central Javanese Islam by Headley, p.363
The Cambridge History of Southeast Asia vol I, p.322; Islamic Revivalism in a Changing Peasant Economy: Central Sumatra, 1784-1847 by Christine Dobbyn, p.118.
The Makings of Indonesian Islam: Orientalism and the Narration of a Sufi Past by Michael Laffan, p.24
A History of Malaysia by Andaya and Andaya, p.52:
However, although the Sufi connection can be established for Aceh, parts of Java and even South Sulawesi, this has not yet been the case for the Malay peninsula in the Melaka period.
Dobbyn, Islamic Revivalism in a Changing Peasant Economy, p.119.
See Leonard Andaya, World of Maluku, p.101-102, 106-107, 112.
Barbara Andaya, To Live As Brothers, p.7
Cummings, Making Blood White, p.49
Language and Power: Exploring Political Cultures in Indonesia by Benedict Anderson, p.127. In both Java and South Sulawesi, the Arabic alphabet came to be associated with sacredness.
The History of Sumatra by William Marsden (1784), p.250
1 Durga's Mosque, p.195-206 and "The Islamization of Central Java: The Role of Muslim Lineages in Kalioso," both by Stephen Headley
The Origins of Islamic Reformism in Southeast Asia: Networks of Malay-Indonesian and Middle Eastern 'Ulamā' in the Seventeenth and Eighteenth Centuries by Azyumardi Azra, p.119-120
The Peasant's Revolt of Banten in 1888: Its Conditions, Course, and Sequel by Sartono Kartodirdjo, p.33-34
The Power of Prophecy: Prince Dipanagara and the End of an Old Order in Java, 1785-1855, p.33-35, section "The golden age of the sikep?"
Population estimates for Melaka are extremely diverse, ranging from 10,000 to 200,000. Similarly, Bantenese population estimates also range from 10,000 to 220,000. The lower estimates are probably more reliable because the higher ones mainly rely on European guesses, which are notoriously unreliable - we know Ayutthaya in Thailand had around 150,000 inhabitants in the 17th century, but Europeans estimated the population at 1,000,000! There is less debate for Makassar, where a population range of 80,000~100,000 is generally accepted for the city itself with another 90,000 people or so living in the suburban peripheries.
See Cambridge History of Southeast Asia vol. I, p.472-476. The chapter is written by Anthony Reid who insists on taking European estimates of city sizes seriously, so keep in mind that many of his urban populations are the highest plausible estimates (but not all, for Ayutthaya or Makassar his numbers are reasonable). For example, his estimate for Melaka's population in 1511 is 100,000 while the Andayas argue for 25,000.
Including Java. Don't let the big temple complexes fool you. From "States without Cities: Demographic Trends in Early Java" (PDF) by Jan Wisseman Christie, p.29:
The only concentrated accumulations of population [in Java] to appear before the fourteenth century seem to have developed around one or two ports, and even these concentrations seem to have fallen short of the size and stability that characterize true urban centers. The capital of Majapahit itself seems to have been little more than a series of large royal and elite compounds with attached religious monuments, surrounded by a cluster of large villages.
By contrast, in 1815 Java had an urbanization rate of 6.7%, with five cities with more than 20,000 people - okay, not very urbanized, but still much more so than in the pre-Islamic era.
A Tale of Two Kingdoms: The Historical Archaeology of Gowa and Tallok, South Sulawesi, Indonesia, PhD thesis by David Bulbeck, p.256.
Reid, "Islamization and Christianization," p.158-160.
Probably due to both their paradoxical society and their enormous success in modern Southeast Asia, there is a very large volume of research on the Minangkabau. My discussion here follows Dobbin's 1984 work Islamic Revivalism in a Changing Peasant Economy and Hadler's 2008 work Muslims and Matriarchs. Unfortunately I haven't kept track of anthropological work.
Dobbin, Islamic Revivalism, p.135; Graves, The Minangkabau Response to Dutch Colonial Rule in the Nineteenth Century, p.33
Chamber-Loir, "Dato' ri Bandang," p.150
Christian Pelras, The Bugis, p.196-197
Hadler, Muslims and Matriarchs, ch. I, "Contention Unending"