It is impossible to fix the precise date of the first introduction of Islam into the Malay Archipelago. It may have been carried thither by the Arab traders in the early centuries of the Hijrah, long before we have any historical notices of such influences being at work.

We may therefore conjecture with tolerable certainty that they must have established their commercial settlements on some of the islands of the Malay Archipelago, as they did elsewhere, at a very early period: though no mention is made of these islands in the works of the Arab geographers earlier than the ninth century,[2] yet in the Chinese annals, under the date a.d. 674, an account is given of an Arab chief, who from later notices is conjectured to have been the head of an Arab settlement on the west coast of Sumatra.[3]

Missionaries must also, however, have come to the Malay Archipelago from the south of India, judging from certain peculiarities of Muslim theology adopted by the islanders. Most of the Muslims  of the Archipelago belong to the Shafiiyyah sect, which is at the present day predominant on the Coromandel and Malabar coasts, as was the case also about the middle of the fourteenth century when Ibn Baṭuṭah visited these parts.[4]

So when we consider that the Muslims of the neighboring countries belong-to the Ḥanafiyyah sect, we can only explain the prevalence of Shafiiyyah teachings by assuming them to have been brought thither from the Malabar coast, the ports of which were frequented by merchants from Java, as well as from China, Yaman and Persia.[5] From India, too, or from Persia, must have come the Shi'ism, of which traces are still found in Java and Sumatra. From Ibn Baṭuṭah we learn that the Muslim Sultan of Samudra had entered into friendly relations with the court of Delhi , and among the learned doctors of the law whom this devout prince especially favored, there were two of Persian origin, the one coming from Shiraz and the other from Ispahan.[6]

But long before this time merchants from the Deccan, through whose hands passed the trade between the Muslim states of India and the Malay Archipelago, had established themselves in large numbers in the trading ports of these islands, where they sowed the seed of the new religion.[7]

It is to the proselytizing efforts of these Arab and Indian merchants that the native Muslim population, which we find already in the earliest historical notices of Islam in these parts, owes its existence. Settling in the centers of commerce, they intermarried with the people of the land, and these heathen wives and the slaves of their households thus formed the nucleus of a Muslim community which its members made every effort in their power to increase. The following description of the methods adopted by these merchant missionaries in the Philippine Islands, gives a picture of what was no doubt the practice of many preceding generations of Muslim traders:—

It must have been in some such way as this that the different Muslim settlements in the Malay Archipelago laid a firm political and social basis for their proselytizing efforts.

With this general statement of the subsidiary means adopted by them, let us follow in detail their proselytizing efforts through the various islands in turn.

Islam introduced into Sumatra

Tradition represents Islam as having been introduced into Sumatra from Arabia. But there is no sound historical basis for such a belief, and all the evidence seems to point to India as the source from which the people of Sumatra derived their knowledge of the new faith.

Active commercial relations had existed for centuries between India and the Malay Archipelago, and the first missionaries to Sumatra were probably Indian traders.[10]

There is, however, no historical record of their labors, and the Malay chronicles ascribe the honor of being the first missionary to Atjeh, in the north-west of Sumatra, to an Arab named Abd Ᾱllah Arif, who is said to have visited the island about the middle of the twelfth century; one of his disciples, Burhan al-Din, is said to have carried the knowledge of the faith down the west coast as far as Priaman.[11]

Untrustworthy as this record is, it may yet possibly indicate the existence of some proselytizing activity about this period; for the Malay chronicle of Atjeh gives 1205 as the date of the accession of Juhan Shah, the traditionary founder of the Muslim dynasty.

He is said to have been a stranger from the West,[12] and to have come to these shores to preach the faith of the Prophet; he made many proselytes, married a wife from among the people of the country, and was hailed by them as their king, under the half-Sanskrit, half-Arabic title of Sri Paduka Sulṭan. For some time the new faith would in all probability have been confined to the ports at which Muslim merchants touched, and its progress inland would be slower, as here it would come up against the strong Hindu influences that had their center in the kingdom of Menangkabau.

Marco Polo, who spent five months on the north coast of Sumatra in 1292, speaks of all the inhabitants being idolaters, except in the petty kingdom of Parlak on the northeast corner of the island, where, too, only the townspeople were Muslims, for "this kingdom, you must know, is so much frequented by the Saracen merchants that they have converted the natives to the Law of Muhammad ,"but the hill-people were all idolaters and cannibals.[13]

Further, one of the Malay chronicles says that it was Sultan Ali Mughayat Shah, who reigned over Atjeh from 1507 to 1522, who first set the example of embracing Islam, in which he was followed by his subjects.[14]

But it is not improbable that the honor of being the first Muslim ruler of the state has been here attributed as an added glory to the monarch who founded the greatness of Atjeh and began to extend its sway over the neighboring country.  He rather effected a revival of, or imparted a fresh impulse to, the religious life of his subjects than gave to them their first knowledge of the faith of the Prophet. For Islam had certainly set firm foot in Sumatra long before his time.

According to the traditionary account of the city of Samudra, the Sharif of Mecca sent a mission to convert the people of Sumatra. The leader of the party was a certain Shaykh  Ismail: the first place on the island at which they touched, after leaving Malabar, was Pasuri (probably situated a little way down the west coast), the people of which were persuaded by their preaching to embrace Islam.

They then proceeded northward to Lambri and then coasted round to the other side of the island and sailed as far down the east coast as Aru, nearly opposite Malacca, and in both of these places their efforts were crowned with a like success.

At Aru they made inquiries for Samudra, a city on the north coast of the island, which seems to have been the special object of their mission, and found that they had passed it. Accordingly they retraced their course to Parlak, where Marco Polo had found a Muslim community a few years before, and having gained fresh converts here also, they went on to Samudra. This city and the kingdom of the same name had lately been founded by a certain Mara Silu, who was persuaded by Shaykh Ismail to embrace Islam, and took the name of al-Malik al-Ṣaliḥ. He married the daughter of the king of Parlak, by whom he had two sons, and in order to have a principality to leave to each, he founded the Muslim city and kingdom of Pasei, also on the north coast.[15]

The king, al-Malik al-Ẕahir, whom Ibn Batutah found reigning in Samudra when he visited the island in 1345, was probably the elder of these two sons.

This prince displayed all the state of Muslim royalty, and his dominions extended for many days journey along the coast; he was a zealous and orthodox Muslim, fond of holding discussions with juris-consults and theologians, and his court was frequented by poets and men of learning. Ibn Baṭuṭah gives us the names of two juris-consults who had come thither from Persia and also of a noble who had gone on an embassy to Delhi  on behalf of the king—which shows that Sumatra was already in touch with several parts of the Muslim world. Al-Malik al- Ẕahir was also a great general, and made war on the heathen of the surrounding country until they submitted to his rule and paid tribute.[16]

Islam had undoubtedly by this time made great progress in Sumatra, and after having established itself along the coast, began to make its way inland. The mission of Shaykh Ismail and his party had borne fruit abundantly, for a Chinese traveler who visited the island in 1413, speaks of Lambri as having a population of 1000 families, all of whom were Muslims "and very good people," while the king and people of the kingdom of Aru were all of the same faith.[17]

Islam and the great kingdom of Menangkabau

It was either about the close of the same century or in the fifteenth century, that the religion of the Prophet found adherents in the great kingdom of Menangkabau, whose territory at one time extended from one shore to another, and over a great part of the island, north and south of the equator.[18]

Though its power had by this time much declined, still as an ancient stronghold of Hinduism it presented great obstacles in the way of the progress of the new religion. Despite this fact, Islam eventually took firmer root among the subjects of this kingdom than among the majority of the inhabitants of the interior of the island.[19]

It is very remarkable that this, the most central people of the island, should have been more thoroughly converted than the inhabitants of so many other districts that were more accessible to foreign influences.

To the present day the inhabitants of the Batak country are still, for the most part, heathen; but Islam has gained a footing among them, e. g. some living on the borders of Atjeh have been converted, by their Muslim neighbors,[20] others dwelling in the mountains of the Rau country on the equator have likewise become Muslims ;[21] on the east coast also conversions of Bataks, who come much in contact with Malays, are not uncommon.[22]

A considerable impulse seems to have been given to Muslim propaganda by the establishment of Christian missions among the Bataks in 1897, and they appear even to have paved the way for its success. Two Batak villages, the entire population of which had been baptized, are said to have gone over in a body to Islam shortly afterwards.[25]

In Central Sumatra there is still a large heathen population, though the majority of the inhabitants are Muslims; but these latter are very ignorant of their religion, with the exception of a few ḥajis and religious teachers: even among the people of Korintji, who are for the most part zealous adherents of the faith, there are certain sections of the population who still worship the gods of their pagan ancestors.[26]

Efforts are, however, being made towards a religious revival, and the Muslim missionaries are making fresh conquests from among the heathen, especially along the west coast.[27]

In the early part of the nineteenth century a religious revival was set on foot in Sumatra, which was not without its influence in promoting the further propagation of Islam.

In 1803 three Sumatran ḥajis returned from Mecca to their native country: during their stay in the holy city they had been profoundly influenced by the Wahhabi movement for the reformation of Islam, and were now eager to introduce the same reforms among their fellow-countrymen and to stir up in them a more zealous religious life. Accordingly they began to preach the strict doctrine of the Wahhabi sect, forbade prayers to saints, drinking and gambling and all other practices contrary to the law of the Quran.

They made a number of proselytes both from among their co-religionists and the heathen population. They later declared a Jihad against the Bataks, and in the hands of unscrupulous and ambitious men the movement lost its original character and degenerated into a savage and bloody war of conquest. In 1821 these so-called Padris came into conflict with the Dutch Government and it was not until 1838 that their last stronghold was taken and their power broken.[34]

From its advantageous situation, in the highway of eastern commerce it soon became a large and flourishing city, and there is little doubt but that Islam was introduced by the Muslim merchants who settled here.[36]

Islam and the Malacca

The Malay chronicle of Malacca assigns the conversion of this kingdom to the reign of a certain Sulṭan Muhammad Shah who came to the throne in 1276. He is said to have been reigning some years before a ship commanded by Sidi Abd al-Aziz came to Malacca from Jiddah, and the king was persuaded by the new-comers to change his faith and to give up his Malay name for one containing the name of the Prophet.[37] But the general character of this document makes its trustworthiness doubtful,[38] in spite of the likelihood that the date of so important an event would have been exactly noted (as was done in many parts of the Archipelago) by a people who, proud of the event, would look upon it as opening a new epoch in their history.

A Portuguese historian gives a much later date, namely 1384, in which year, he says, a Qadhi came from Arabia and having converted the king, gave him the name of Muhammad after the Prophet, adding Shah to it.[39]

Islam and Queda Kingdom
In the annals of Queda, one of the northernmost of the states of the Malay Peninsula, we have a curious account of the introduction of Islam into this kingdom, about a.d. 1501,[40] which (divested of certain miraculous incidents) is as follows:

The Raja now built mosques wherever the population was considerable, and directed that to each there should be attached forty-four of the inhabitants at least as a settled congregation, for a smaller number would have been few for the duties of religion.

So mosques were erected and great drums were attached to them to be beaten to call the people to prayer on Fridays. Shaykh Abd Allah continued for some time to instruct the people in the religion of Islam; they flocked to him from all the coasts and districts of Queda and its vicinity, and were initiated by him into its forms and ceremonies.

The news of the conversion of the inhabitants of Queda by Shaykh Abd Allah reached Atjeh, and the Sultan of that country and a certain Shaykh Nur al-Din, an Arab missionary, who had come from Mecca, sent some books and a letter, which ran as follows:—

It must not be supposed that the labors of Shaykh Abd Allah were crowned with complete success, for we learn from the annals of Atjeh that a Sultan of this country who conquered Queda in 1649, set himself to "more firmly establish the faith and destroy the houses of the Liar "or temples of idols.[43] Thus a century and a half elapsed before idolatry was completely rooted out.

We possess no other details of the history of the conversion of the Malays of the Peninsula, but in many places the graves of the Arab missionaries who first preached the faith to them are honored by these people.[44]

Their long intercourse with the Arabs and the Muslims of the east coast of India has made them very rigid observers of their religious duties, and they have the reputation of being the most exemplary Muslims of the Archipelago; at the same time their constant contact with the Hindus, Buddhists, Christians and pagans of their own country has made them liberal and tolerant.

They are very strict in the keeping of the fast of Ramaḍan and in performing the pilgrimage to Mecca. The religious interests of the people are always considered at the same time as their temporal welfare; and when a village is found to contain more than forty houses and is considered to be of a size that necessitates its organization and the appointment of the regular village officers, a public preacher is always included among the number and a mosque is formally built and instituted.[45]

In the north, where the Malay states border on Siam, Islam has exercised considerable influence on the Siamese Buddhists; those who have here been converted are called Samsams and speak a language that is a mixed jargon of the languages of the two people.[46] Converts are also made from among the wild tribes of the Peninsula,[47]

The history of the spread of Islam in Indo-China is obscure; Arab and Persian merchants probably introduced their religion into the sea-port towns from the tenth century onwards, but its most important expansion was due to the immigrations of Malays which began at the close of the fourteenth century.[48]