First Sudanese Civil War The First Sudanese Civil War ( also known as the Anyanya Rebellion or Anyanya I , after the name of the rebels ) was a conflict from 1955 to 1972 between the northern part of Sudan and the southern Sudan region that demanded representation and more regional autonomy . Half a million people died over the 17 years of war , which may be divided into three stages : initial guerrilla war , Anyanya , and South Sudan Liberation Movement . However , the agreement that ended the First Sudanese Civil War ' s fighting in 1972 failed to completely dispel the tensions that had originally caused it , leading to a reigniting of the north - south conflict during the Second Sudanese Civil War , which lasted from 1983 to 2005 . The period between 1955 and 2005 is thus sometimes considered to be a single conflict with an eleven - year ceasefire that separates two violent phases . Origins of the conflict . Until 1946 , the British government , in collaboration with the Egyptian government ( under a condominium governing arrangement ) administered south Sudan and north Sudan as separate regions . At this time , the two areas were merged into a single administrative region as part of British strategy in the Middle East . This act was taken without consultation with southerners , who feared being subsumed by the political power of the larger north . Southern Sudan is inhabited primarily by Christians and animists and considers itself culturally sub - Saharan , while most of the north is inhabited by Muslims who were culturally Arabic . After the February 1953 agreement by the United Kingdom and Egypt to grant independence to Sudan , the internal tensions over the nature of the relationship of north to south were heightened . Matters reached a head as the 1 January 1956 independence day approached , as it appeared that northern leaders were backing away from commitments to create a federal government that would give the south substantial autonomy . Course of the war . On 18 August 1955 , members of the British - administered Sudan Defence Force Equatorial Corps mutinied in Torit , and in the following days in Juba , Yei , and Maridi . The immediate causes of the mutiny were a trial of a southern member of the national assembly and an allegedly false telegram urging northern administrators in the South to oppress Southerners . The mutinies were suppressed , though survivors fled the towns and began an uncoordinated insurgency in rural areas . Poorly armed and ill - organized , they were little threat to the outgoing colonial power or the newly formed Sudanese government . O ' Ballance , writing in 1977 , says that the ' period from 1955 to 1963 was simply one of guerilla survival , scarcely removed from banditry , and that it was successful due to a score or so of former southern army officers and warrant officers , and a small number of non - commissioned officers . ' However , the insurgents gradually developed into a secessionist movement composed of the 1955 mutineers and southern students . These groups formed the " Anyanya " guerrilla army . ( Anyanya is also known as " Anyanya 1 " in comparison to Anyanya 2 , began with the 1974 mutiny of the military garrison in Akobo . ) Starting from Equatoria , between 1963 and 1969 Anyanya spread throughout the other two southern provinces : Upper Nile and Bahr al Ghazal . However , the separatist movement was crippled by internal ethnic divisions . O ' Ballance writes that one of the Sudanese army ' s four infantry brigades had been stationed in Equatoria Province since 1955 , being periodically reinforced as required . The government was unable to take advantage of rebel weaknesses because of their own factionalism and instability . The first independent government of Sudan , led by Prime Minister Ismail al - Azhari , was quickly replaced by a stalemated coalition of various conservative forces , which was in turn overthrown in the coup d ' état of Chief of Staff Lt . Gen . Ibrahim Abboud in 1958 . Resentment at the military government led to a wave of popular protests that led to the creation of an interim government in October 1964 . These protests were the first appearance of Islamist Hassan al - Turabi , who was then a student leader . Between 1966 and 1969 , a series of Islamist - dominated administrations proved unable to deal with the variety of ethnic , economic and conflict problems afflicting the country . After a second military coup on 25 May 1969 , Col . Gaafar Nimeiry became Prime Minister and promptly outlawed political parties . In - fighting between Marxist and non - Marxist factions in the ruling military class led to another coup in July 1971 and a short - lived administration by the Sudanese Communist Party before anti - Communist factions put Nimeiry back in control of the country . That same year , German national Rolf Steiner , who had been clandestinely advising the rebels , was captured in Kampala , Uganda and deported to Khartoum , where he was put on trial for his anti - government activities . Originally sentenced to death , he would serve three years in prison before being released following pressure from the West German Government . In 1971 , former army lieutenant Joseph Lagu 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 . Effects of the war . Five hundred thousand people , of which only one in five was considered an armed combatant , were killed in the seventeen years of war and hundreds of thousands more were forced to leave their homes . The Addis Ababa Agreement proved to be only temporary respite . Infringements by the north led to increased unrest in the south starting in the mid - 1970s , leading to the 1983 army mutiny that sparked the Second Sudanese Civil War .