The expansion of Islam coincides with the…

The expansion of Islam coincides with the decline of the Nubian Christian church.

A "dark age" envelops Nubia in the fifteenth century during which political authority fragments and slave raiding intensifies.

Communities in the river valley and savanna, fearful for their safety, form tribal organizations and adopt Arab protectors.

Muslims probably do not constitute a majority in the old Nubian areas until the fifteenth or sixteenth century.