Why was Islam so readily adopted by rulers within Sudan?

Islam is the largest religion in Sudan, and Muslims have dominated national government institutions since independence in 1956. Statistics indicate that the Muslim population is approximately 75%-80%, including numerous Arab and non-Arab groups. The remaining 20% ascribe to either Christianity (approximately 5% of the total population) or traditional animist religions. Muslims predominate in the north, but there are sizable Christian communities in northern cities, principally in areas where there are large numbers of internally displaced persons. It is estimated that over the last forty years, more than 4 million southerners have fled to the north to escape the war. Most citizens in the south adhere to either Christianity or traditional indigenous (animist) religions; however, there are many Muslim adherents as well, particularly along the historical dividing line between Arabs and Nilotic ethnic groups.

The Muslim population is almost entirely Sunni but is divided into many different groups. The most significant divisions occur along the lines of the Sufi brotherhoods. Two popular brotherhoods, the Ansar and the Khatmia, are associated with the opposition Umma and Democratic Unionist Parties respectively.

Shari'a law and its application to non-Muslims in the capital was a contentious issue during the negotiations, but it and the other major issues underlying the north/south conflict have been largely resolved in the agreements. Shari'a generally is to continue to be the basis of the national legal system as it applies in the north; national legislation applicable to the south is to be based on "popular consensus, the values, and the customs of the people." In states or regions where a majority hold different religious or customary beliefs than those on which the legal system is based, the national laws may be amended to accord better with such beliefs. Throughout the country, the application of Shari'a to non-Muslims is to be limited, and courts may not exercise their discretion to impose the harsher physical forms of Shari'a penalties on non-Muslims.