Answer:
After the conquest of North Africa by Muslim Arabs in the 7th century CE, Islamic culture spread throughout West Africa via merchants, traders, scholars, and missionaries, that is largely through peaceful means whereby African rulers either tolerated the religion or converted to it themselves. In this way, Islam expanded across and around the Sahara Desert. In addition, the religion arrived in East Africa when Arab traders crossed the Red Sea and, in a second wave, settled along the Swahili Coast. Military campaigns did occur from the 14th century CE against the Christian kingdoms of Nubia, for example, while in the 18th century CE the Muslim Fulani launched a holy war in the Lake Chad region. There were also sometimes violent resistance by supporters of traditional African beliefs such as animism and fetish, spirit and ancestor worship.
