Islam has, for the past 500 years, been the dominate religion of the
savanna and desert regions of Sudan, including the upper Nile Valley.
The Nilotic and tropical Africans of the South have been substantially
Christianized, but there is a significant number of Muslims and many
people continue practicing traditional African religions. On the whole,
Sudan claims to be about 70% Muslim. Sufism is quite pronounced in
Sudan, but there are various schools of Islam interpretation.