Within the newly autonomous Sudan , a divide was growing. The southern part of the country began calling for a federal system that would allow it a level of autonomy from the central government. Khartoum refused, provoking a mutiny by southern military officials that launched Sudan’s first civil war, lasting from 1955 to 1972.
The northern Sudanese sought, almost from the beginning, to unify the country under Arab-Muslim control, based in the north. In doing so, they alienated Christians and animists in the South, as well as other marginalized groups. Arabization and Islamicization efforts crystallized southern opposition to the central government, although the South was split over whether it wanted a federal system or complete independence from the North. A series of civilian governments through the 1960s exacerbated the divide between the North and South by refusing to grant any degree of self-determination to southern Sudan .
Secular socialist leader Col. Gaafar Muhammed Nimeiri, who took power in 1969, crafted a policy granting autonomy to the south and signed it into agreement in 1972. Southerners showed their appreciation by helping Col. Nimeiri put down two coup attempts. However, his early support was swept away when mounting opposition forced him to abandon his unpopular support for the South.
Strong support for an Islamic state and the discovery of oil in the south were the final blows to the south’s plea for autonomy. Nimeiri eliminated the separate southern region in 1983, putting control in the hands of the central government and making Arabic the official language there as well. The decision launched the Sudan’s second civil war and gave birth to the Sudanese People’s Liberation Movement and Army. (SPLA/M).