Sudan was embroiled in two prolonged civil wars during most of the remainder of the 20th century. These conflicts were rooted in northern economic, political, and social domination of non-Muslim, non-Arab southern Sudanese. The first civil war ended in 1972, but broke out again in 1983. The second war and famine-related effects resulted in more than 2 million deaths and over 4 million people displaced over a period of two decades. Peace talks gained momentum in 2002-04 with the signing of several accords; a final Naivasha peace treaty of January 2005 granted the southern rebels autonomy for six years, after which a referendum for independence is scheduled to be held.