This is an accepted version of this page Islam is the largest religion in Indonesia, with 87.06% of the Indonesian population identifying themselves as Muslims, based on civil registry data in 2023.

Islam in Indonesia is considered to have gradually spread through merchant activities by Arab Muslim traders, adoption by local rulers, and the influence of Sufism since the 13th century.

Together, these non-Muslim areas originally constituted more than one-third of Indonesia prior to the massive transmigration effort sponsored by the Suharto government and recent spontaneous internal migration.

Regardless of its intent, the economic and political consequences of the transmigration policy contributed to religious conflicts in Maluku, Central Sulawesi, and to a lesser extent, Papua.

Abangan was considered an indigenous blend of native and Hindu-Buddhist beliefs with Islamic practices sometimes also called Javanism, kejawen, agama Jawa, or kebatinan.

[20] The Kebatinan or Kepercayaan has no certain prophet, sacred book, nor distinct religious festivals and rituals; it has more to do with each adherent's internalized transcendental vision and beliefs in their relations with the supreme being.

[20] These spirits are believed to inhabit natural objects, human beings, artifacts, and grave sites of important wali (Muslim saints).

[33] Nahdlatul Ulama (NU), the largest traditionalist organization, focuses on many of the activities such as social, religious and education and indirectly operates a majority of the country's Islamic boarding schools.

[47] Through assimilation related to trade, royal conversion, and conquest,[citation needed] however, Islam had supplanted Hinduism and Buddhism as the dominant religion of Java and Sumatra by the end of the 16th century.

[citation needed] As port towns adopted Islam, it undermined the waning power of the east Javanese Hindu/Buddhist Majapahit kingdom in the 16th century.

This last Hindu kingdom in Java fell under the rising power of the Islamized Sultanate of Demak in the 1520s; in 1527, the Muslim ruler renamed newly conquered Sunda Kelapa as Jayakarta meaning "precious victory", which was eventually contracted to Jakarta.

Soon after, traditionalist Nahdlatul Ulama (NU) was founded in 1926 by Hasyim Asy'ari, another disciple of al-Minangkabawi, in response to the perceived growing threat of reformist waves.

A combination of reformist thoughts and the growing sense of sovereignty had led to the brief development of Islam as a vehicle for the political struggle against the Dutch colonialism.

[22] A similar Islamic-nationalist organization Union of Indonesian Muslims (PERMI) faced severe crackdown by the Dutch colonial government, leading to the arrest of its members including Rasuna Said.

This created a vacuum within the Muslim community for the leadership role, filled by civil society organizations such as Muhammadiyah, NU, more puritanical PERSIS, and Al-Irshad Al-Islamiya.

[citation needed] Harun Nasution was a pioneering scholar adhered to the humanist and rationalist perspectives in Indonesian intellectual landscape, advocating for a position described as neo-Mutazilite.

[62] Nurcholish Madjid (Cak Nur) was a highly influential scholar who is credited for cultivating the modernist and reformist discourse, primarily influenced by Pakistani Islamic philosopher Fazlur Rahman.

This status had drastically changed through the course of endeavor by the organizations such as the Indonesian Islamic Dawah Council (DDII) led by Mohammad Natsir, not to mention aforementioned Muhammadiyah, NU, and PERSIS.

[65] More recently, organizations such as DDII and LIPIA have been acting as instruments of the propagation of Salafism or Wahhabism with funding from Saudi Arabia and other Gulf monarchies,[66][67][68] that "has contributed to a more conservative, more intolerant atmosphere"[69] and eager to strip heritages of traditional Indonesian Islam of local customs influenced by Animism ritual and Sufi teaching.

[73] Initially hoped as the ally of Islamic groups, the New Order quickly became the antagonist following its attempt to reform educational and marital legislation to more secular-oriented code.

During the early 2000s, the return of Abu Bakar Bashir, who was in exile during the Suharto era as a spiritual leader of Jihadism in Indonesia, resulted in the series of bombing attacks,[e] which have been largely contained recently.

[82][83] Conservative development has seen the emergence of vigilante group Islamic Defenders Front (FPI),[84] persecution against Ahmadiyya exemplified by MUI's fatwa,[26] and the nationwide protest in 2016 against the incumbent governor of Jakarta Basuki Tjahaja Purnama (Ahok) accused of blasphemy.

King Raden Patah of Demak, Java, wanted to see the wayang in its traditional form but failed to obtain permission from Muslim religious leaders.

In West Sumatra, there is also a tradition of multi-purpose religious architecture known as surau which is often built in vernacular Minangkabau style as well, with three- or five-tiered roofs and woodcarvings engraved in the facade.

Minaret was not introduced to full extent until the 19th century,[97] and its introduction was accompanied by the importation of architectural styles of Persian and Ottoman origin with the prominent usage of calligraphy and geometric patterns.

In February 2010, following the latest Hajj, the Department of Religious Affairs drew sharp criticism for mismanaging the registration of approximately 30,000 prospective pilgrims after they had paid the required fees.

Proponents of an Islamic state argued unsuccessfully in 1945 and throughout the parliamentary democracy period of the 1950s for the inclusion of language (the "Jakarta Charter") in the Constitution's preamble making it obligatory for Muslims to follow shari'a.

[citation needed] On 9 May 2017, Indonesian politician Basuki Tjahaja Purnama was sentenced to two years in prison by the North Jakarta District Court after being found guilty of committing blasphemy.

Because Muslims make up the overwhelming majority of Aceh's population, the public largely accepted shari'a, which in most cases merely regularised common social practices.

Observers link it to the influence of the Wahhabist Hijrah movement, something that the Indonesian government wants to curb as it feels it threatens the country's secular values and unity.