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.
First Sudanese Civil War
The South was first led by the late leader Aggrey Jaden; he left the movement in 1969 due to internal political disputes. In the same year Gordon Muortat Mayen was elected unanimously as the new leader of the South. Southern Sudan in this time changed their name to the Nile Republic and resumed warfare against Khartoum, however some of the former leader Jaden's troops would not accept a Dinka leader and fought against the Anyanya. In 1971, former army lieutenant Joseph Lagu formed a successful coup d'état against Gordon Muortat with help from Israel, which pledged him their support. He then gathered all the guerilla bands under his Southern Sudan Liberation Movement (SSLM). This was the first time in the history of the war that the separatist movement had a unified command structure to fulfill the objectives of secession and the formation of an independent state in South Sudan. It was also the first organization that could claim to speak for, and negotiate on behalf of, the entire south. Mediation between the World Council of Churches (WCC) and the All Africa Conference of Churches (AACC), both of which spent years building up trust with the two combatants, eventually led to the Addis Ababa Agreement of March 1972 ending the conflict. In exchange for ending their armed uprising, southerners were granted a single southern administrative region with various defined powers. However, this agreement was denounced as a sellout by former leaders Aggrey Jaden and Gordon Muortat Mayen. The agreement's demise was predicted by both, with Muortat going on to form and lead the African National Front, an opposition movement against the Addis Ababa talks and agreement, and also in 1975, the Anyanya Patriotic Front — a new liberation movement with the same aims as SSPG, NPG and the first Anyanya — to liberate the South as a separate country from the North. The civil war was finally restarted, this time under John Garang.