The proximity of the cradle of Islam in the Arabian Peninsula to the East African coast led to the new religion’s early arrival in East Africa and the absorption of Arabic influences. East African Islam was also influenced by the central position of the coast on the trade route between the Middle East and the Far East and by relations with Persia and Yemen. The geographical position of the East African coast contributed to the development of the Swahili culture and language, which combined external Islamic elements with local ethnic, religious, and linguistic features.
Archeological and numismatic evidence indicate the existence of a Muslim settlement at Shanga in the Lamu archipelago on the Kenyan coast as early as 780. Evidence of Muslim settlement between the 10th and 13th centuries has been found in Pemba, Zanzibar, and Kilwa, which are all in present- day Tanzania. In the course of the 14th century, Islam spread along the coastline up to the Comoro Islands and Madagascar and into the hinterland. It is estimated that by the 14th century, there were more than 30 Muslim communities. These communities were composed of Eastern Bantu, Sudanic and Southern Cushitic, and Northeast- Coastal Bantu speakers, together with communities of Arabic, Indian, Persian, and Yemenite immigrants, mostly traders and merchants.
The concept of a supreme God was found already in the preIslamic beliefs of the region, but it was associated with the worship of spirits and ancestors. Some of these pre- Islamic beliefs were assimilated into the new religion, as observed by later travelers, such as Abu ‘Abdallah Muhammad b. Battuta in the 14th century. The existence of immigrants that came from the town of Shiraz in Persia suggests that Persian forms of Islam may have been present at an early stage, which may have led to the introduction of Shi’i elements. Yet the Fatimid dynasty’s dominance in trade with India and the East Indies along the Red Sea since the 11th century resulted in the dominance of Sunni influences in the area. With the migration of shurafā’ (plural of sharīf) families from Yemen and the Hadhramaut beginning in the 13th century, local Muslims adopted the Shafi’i madhhab (one of the four schools of law in Islam). It is in urban settlements such as Mombasa, Zanzibar, Kilwali, and Kilwa, which flourished between the 12th and 14th centuries, that these developments can be traced. Kilwa was the most powerful Islamic settlement on the coast, known for its Islamic architecture, governance, and center of learning, as well as its jihad against the “infidels” of the hinterland.
The Portuguese conquest of the East African coast, which occurred from 1498 to 1530, threatened to wipe out the age of Islamic prosperity. As part of their attempts to secure control of the maritime trade routes against the Ottomans, the Portuguese established Fort Jesus in Mombasa and subjugated most of the Muslim settlements along the coast. Powerful Islamic settlements such as Kilwa declined, and new centers, such as Lamu and Pate, emerged with new ruling elites, mostly from shurafā’ families. Islamic scholarship began to flourish on the coast, including written literature in both Arabic and Swahili. Attempts to convert coastal Muslims to Christianity were rarely successful and led local Muslims to seek external aid in order to expel the Portuguese.
During the 17th century, the sultanate of Oman became a considerable force in the Indian Ocean. At the request of local Swahili leaders, such as the Mazru’i dynasty from Mombasa, the Omanis helped the latter expel the Portuguese from all areas north of Mozambique at the beginning of the 18th century. The Omanis gradually began to conquer areas along the coast, however, and during the 1820s they established the Zanzibar Sultanate. In 1837, Sa’id b. Sultan from the Al Bu Sa’idi dynasty made Zanzibar his main place of residence. Through the influence of the new sultanate, a more Arabized form of East African Islam flourished until the arrival of the Europeans.
European protectorates were established over Zanzibar, Tanganyika (both which are in present- day Tanzania), Kenya, Uganda, and other territories toward the end of the 19th century. European colonial rule was generally based on indirect rule, in other words, on collaboration with local Muslim rulers who continued their traditional ruling systems. Sufi tarīqas (Sufi brotherhoods) such as the ‘Alawis, Qadiris, and Shadhilis, which had flourished in the area in previous centuries, became the main basis for social organization and the spread of Islam over new communities during the colonial era. Many workers who emigrated from the hinterland to the coastal areas were also converted to Islam. Yet European colonialism also encouraged Christian missionary activity and colonization of European settlers, which resulted in a notable decrease in Islamic diffusion. Thus, with the rise of the East African secular nation-states in the early 1960s, Muslims were substantial minorities in the new states but not a dominant factor in the determination of political and ideological agendas.
Since the 1980s, feelings of marginalization of Muslims in states dominated by Christians elites such as Kenya and Uganda have resulted in an Islamic revival, accompanied by politicization and even radicalization. Influences from revolutionary Iran and Saudi Arabian Wahhabism have resulted in the establishment of educational