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.
Foreign relations of South Sudan
Sudan was the first country to recognise the independence of South Sudan on 8 July 2011, 1 day prior to independence. Four other states followed suit on 8 July. Over 25 countries had recognised the country on 9 July, including all permanent members of the United Nations Security Council.