It was initially believed that Islam penetrated Indonesian society in a largely peaceful way, (which is still largely true according to many scholars) and from the 14th century to the end of the 19th century the archipelago saw almost no organised Muslim missionary activity. Later findings of scholars say that some parts of Java, i.e.
Sunda kingdom West Java and the kingdom of
Majapahit on East Java was conquered by Javanese Muslims. The Hindu-Buddhist Sunda Kingdom of
Pajajaran was conquered by Muslims in the 16th century, while the Muslim-coastal and Hindu-Buddhist-interior part of East Java was often at war.
Northern Sumatra with traditional
Minangkabau architecture Firmer evidence documenting continued cultural transitions comes from two late-14th century gravestones from
Minye Tujoh in
North Sumatra, each with Islamic inscriptions but in Indian-type characters and the other Arabic. Dating from the 14th century, tombstones in
Brunei,
Terengganu (northeast
Malaysia) and
East Java are evidence of Islam's spread. The Trengganu stone has a predominance of
Sanskrit over Arabic words, suggesting the representation of the introduction of Islamic law. According to the ''Ying-yai Sheng-lan: The overall survey of the ocean's shores' (1433)'' a written account by
Zheng He's chronicler and translator
Ma Huan: "the main states of the northern part of
Sumatra were already
Islamic
Sultanates. In 1414, he visited the
Malacca Sultanate, its ruler
Iskandar Shah was
Muslim and also his people, and they were very strict believers". In Kampong Pande, the tombstone of Sultan
Firman Syah, the grandson of Sultan
Johan Syah, has an inscription stating that Banda Aceh was the capital of the
Kingdom of Aceh Darussalam and that it was built on Friday, 1 Ramadhan (22 April 1205) by Sultan Johan Syah after he defeated the Hindu and Buddhist Kingdom of
Indra Purba whose capital was
Bandar Lamuri. The establishment of further Islamic states in North Sumatra is documented by late 15th- and 16th-century graves including those of the first and second Sultans of Pedir;
Muzaffar Syah, buried (1497) and
Ma’ruf Syah, buried (1511).
Aceh was founded in the early 16th century and would later become the most powerful North Sumatran state and one of the most powerful in the whole Malay archipelago. The Aceh Empire's first sultan was
Ali Mughayat Syah whose tombstone is dated (1530). The book of Portuguese apothecary
Tomé Pires that documents his observations of Java and Sumatra from his 1512 to 1515 visits, is considered one of the most important sources on the spread of Islam in Indonesia. In 1520, Ali Mughayat Syah started military campaigns to dominate the northern part of Sumatra. He conquered Daya, and submitted the people to Islam. Further conquests extended down the east coast, like
Pidie and
Pasai incorporating several pepper-producing and gold-producing regions. The addition of such regions ultimately led to internal tensions within the Sultanate, as Aceh's strength was as a trading port, whose economic interests vary from those of producing ports. At this time, according to Pires, most Sumatran kings were Muslim; from Aceh and south along the east coast to
Palembang the rulers were Muslim, while south of Palembang and around the southern tip of Sumatra and up the west coast, most were not. In other Sumatran kingdoms, such as
Pasai and
Minangkabau the rulers were Muslim although at that stage their subjects and peoples of neighboring areas were not, however, it was reported that the religion was continually gaining new adherents. After the arrival of the
Portuguese colonials and the tensions that followed regarding control of the
spice trade, the
Acehnese Sultan
Alauddin al-Kahar (1539–71) sent an embassy to the
Ottoman Sultan
Suleiman the Magnificent in 1564, requesting Ottoman support against the
Portuguese Empire. The Ottomans then dispatched their admiral
Kurtoğlu Hızır Reis he set sail with a force of 22
ships carrying soldiers, military equipment and other supplies. According to accounts written by the Portuguese Admiral
Fernão Mendes Pinto, the Ottoman fleet that first arrived in
Aceh consisted of a few
Turks and largely of
Muslims from the ports of the
Indian Ocean.
East Sumatra and Malay peninsula Founded around the beginning of the 15th century by
Sultan Parameswara, the great Malay trading state
The Sultanate of Malacca founded by
Sultan Parameswara, was, as the most important trading center of the Southeast Asian archipelago, a center of foreign Muslims, and it thus appears a supporter of the spread of Islam.
Parameswara, himself is known to have converted to
Islam, and taken the name Iskandar Shah after
the arrival of the
Hui-Chinese Admiral
Zheng He. From Malacca and elsewhere, gravestones survive showing not only its spread in the Malay archipelago but as the religion of a number of cultures and their rulers in the late 15th century.
Central and eastern Java , the first Muslim state in Java Inscriptions in
Old Javanese rather than Arabic on a significant series of gravestones dating back to 1369 in East Java, indicate that these are almost certainly
Javanese, rather than foreign Muslims. Due to their elaborate decorations and proximity to the site of the former Hindu-Buddhist Majapahit capital, Damais concludes that these are the graves of very distinguished Javanese, perhaps even royalty. This suggests that some of the Javanese elite adopted Islam at a time when the Hindu-Buddhist Majapahit was at the height of its glory. Ricklefs (1991) argues that these east Javan gravestones, sited and dated at the non-coastal
Majapahit, cast doubt on the long-held view that Islam in Java originated on the coast and represented political and religious opposition to the kingdom. As a kingdom with far-reaching political and trading contacts, Majapahit would have almost certainly been in contact with Muslim traders, however there is conjecture over the likelihood of its sophisticated courtiers being attracted to a religion of merchants. Rather, mystical
Sufi Muslim teachers, possibly claiming supernatural powers (
keramat), are thought to be a more probable agent of religious conversion of Javanese court elites, who had long been familiar with aspects of Hindu and Buddhist mysticism. Since the east Javan gravestones were those of Javanese Muslims fifty years before, Ma Huan's report indicates that Islam may have indeed been adopted by Javanese courtiers before the coastal Javanese. An early Muslim gravestone dated AH 822 (AD 1419) has been found at
Gresik an East Javanese port and marks the burial of
Malik Ibrahim. As it appears, however, that he was a non-Javanese foreigner, the gravestone does not provide evidence of coastal Javanese conversion. Malik Ibrahim was, however, according to Javanese tradition one of the first nine apostles of Islam in Java (the
Wali Sanga) although no documentary evidence exists for this tradition. In the late 15th century, the powerful
Majapahit empire in Java was at its decline. After having been defeated in several battles, the last
Hindu kingdom in Java fell under the rising power of Islamised Kingdom of
Demak in 1520.
Western Java Pires'
Suma Oriental reports that
Sundanese-speaking
West Java was not Muslim in his day, and was indeed hostile to Islam. He presents evidence that
Sunan Gunungjati was initiated into the
Kubra, and
Shattari, orders of
sufism.
Other areas There is no evidence of the adoption of Islam by Indonesians before the 16th century in areas outside of Java, Sumatra, the sultanates of
Ternate and
Tidore in
Maluku, and Brunei and the Malay Peninsula. ==Indonesian and Malay legends==