query: When did Sudan become a republic?
passage: History of Sudan (1956–69)
On 1 January 1956 Anglo-Egyptian Sudan became the independent Republic of the Sudan. Before 1955, however, the government under Ismail al-Azhari had temporarily halted Sudan's progress toward self-determination, hoping to promote unity with Egypt. Despite his pro-Egyptian National Unionist Party (NUP) winning a majority in the 1953 parliamentary elections, however, Azhari realized that popular opinion had shifted against such a union. Azhari, who had been the major spokesman for the "unity of the Nile Valley", therefore reversed the NUP's stand and supported Sudanese independence. On December 19, 1955, the Sudanese parliament, under Azhari's leadership, unanimously adopted a declaration of independence that became effective on January 1, 1956. Azhari called for the withdrawal of foreign troops and requested the condominium powers to sponsor a plebiscite in advance.
passage: The Citizen (South Sudan)
The newspaper was first founded during the second period of autonomy for what was then known as Southern Sudan, the ten states in the deep south of the Republic of the Sudan, in 2006. It became South Sudan's largest newspaper when the country formally declared independence on 9 July 2011.