Excerpts from Books and Wikipedia
"This newest state to appear on the world political map became independent in 2011, the outcome of a near-unanimous referendum in the southern provinces of former Sudan (…). South Sudan’s birth came in the aftermath of six disastrous decades of postcolonial strife within former Sudan, a brutal conflict in which more than 1.5 million died, magnified by the bifurcation of the country along the religious divide between Islam and Christianity-animism that we know as the Islamic Front. The British effectively ruled former Sudan from the 1890s until independence in 1956. One of the roots of the country’s long-running internal conflict, which peaked in the resumption of its post-independence civil war between 1983 and 2005, lay in the decision of the British colonial administration to combine northern Sudan, which was heavily Arabized and Islamized, with a sizeable African/Christian-dominated area to the south. As soon as the British departed in the mid-1950s, the Khartoum-based regime in the north sought to impose its Islamic rule on southern Sudan, immediately triggering the first civil war that lasted until 1972." [Geography: Realms, Regions, and Concepts, 17th Edition, p. 316]