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.
Flag of South Sudan
The flag of South Sudan was adopted following the signing of the Comprehensive Peace Agreement that ended the Second Sudanese Civil War. A similar version of the flag was previously used as the flag of the Sudan People's Liberation Movement. The flag of South Sudan is older than the country itself, as the flag was adopted in 2005, while the country became independent in 2011.