620s–19th Century: (Cross and Crescent in Northeast Africa — The First Mosque on the Continent at Massawa, Islam Advancing from the Somali Coast by the Tenth…

620s–19th Century: (Cross and Crescent in Northeast Africa — The First Mosque on the Continent at Massawa, Islam Advancing from the Somali Coast by the Tenth Century, Ethiopia as a Christian Island in a Stormy Muslim Sea, the Oromo Transforming Harar into a Muslim Settlement, Jiberti Muslim Merchants in the Christian Highlands, and the Qadiriyya Expanding into Somalia and Eritrea): The first Muslims in Africa arrived on the Eritrean coast — the first mosque on the continent was in Massawa, possibly built by members of the Prophet’s own family in the 620s or 630s. By the tenth century, Islam was advancing into the region of modern Somalia, Djibouti, Ethiopia, and Eritrea from the Somali coast. Some have seen the defining characteristic as a fundamental struggle between Christianity and Islam that continues to the present day, but there was much cooperation and peaceful coexistence, notably in commerce. The Ethiopian state deliberately cultivated the image of a Christian kingdom deep in the highlands, isolated and surrounded by hostile Muslims — the Bible loomed large in the highland imagination, and the Christian polity saw itself as a second Israel. The Oromo, who advanced to occupy the southern third of present-day Ethiopia by the end of the sixteenth century, transformed Harar into a Muslim settlement of significance — the Harar sultanate became an important regional power through its connections with the Funj sultanate in Sudan. Meanwhile, expanding Red Sea trade networks greatly benefited Muslim merchants, who came to constitute a distinct class known as jiberti across the central and northern Ethiopian highlands. Sufi brotherhoods facilitated the spread of Islam across the region — the Qadiriyya expanded from Harar into Somalia and Eritrea, while the Salihiyya and Ahmadiyya were active among the Somali. By the nineteenth century, the Somali constituted an Islamic population adjacent to the Oromo, dominating an enormous swathe of northeast Africa.