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.
Southern Sudan Autonomous Region (1972–83)
The Southern Sudan Autonomous Region was an autonomous region that existed in Southern Sudan between 1972 and 1983. It was established on 28 February 1972 by the Addis Ababa Agreement which ended the First Sudanese Civil War. The region was abolished on 5 June 1983 by the administration of Sudanese President Gaafar Nimeiry. Revocation of southern autonomy was one of the causes of the Second Sudanese Civil War which would continue until January 2005, when southern autonomy was restored.