History of Sudan
The modern Republic of Sudan was formed in 1956 and inherited its boundaries from Anglo-Egyptian Sudan, established in 1899. For times predating 1899, usage of the term "Sudan" for the territory of the Republic of Sudan was somewhat anachronistic, and may have referred to the more diffuse concept of the Sudan.
Equatoria
In February 1953, the United Kingdom and Egypt reached an agreement providing for Sudanese self-government and self-determination. On January 1, 1956 Sudan gained independence from the British and Egyptian governments. The new state was under the control of the Arab led Khartoum government. The Arab Khartoum government had promised Southerners full participation in the political system, however, after independence the Khartoum government reneged on its promises. Southerners were denied participation in free elections and marginalized from political power. The government actions created resentment in the South that led to a mutiny by a group of Equatorians sparking the 21 year civil war (1955–1972, 1983 to 2004).