The most significant factor that helped the spread of Islam into major empires in Africa was trade. Islam spread along major trade routes, particularly across the Sahara Desert and along the East African coast. The Arab traders who traveled these routes played a crucial role in spreading Islamic ideas, practices, and beliefs.
Trade allowed for cultural and religious exchange, as well as the establishment of economic and political ties between Muslim traders and local African rulers. Over time, many African rulers and elites converted to Islam, which further facilitated the spread of the religion throughout the empires.
Additionally, the peaceful and tolerant nature of Islam, combined with its appeal to various African communities seeking spiritual guidance and protection, contributed to its acceptance and adoption in many regions.
While other factors such as military conquest and migration also played a role, trade was the most influential factor in the spread of Islam into major empires in Africa.