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.
Sudan
From 1820 to 1874 the entirety of Sudan was conquered by the Muhammad Ali dynasty. Between 1881 and 1885 the harsh Egyptian reign was eventually met with a successful revolt led by the self-proclaimed Mahdi Muhammad Ahmad, resulting in the establishment of the Caliphate of Omdurman. This state was eventually destroyed in 1898 by the British, who would then govern Sudan together with Egypt.