Old kingdoms were flourishing when Portuguese mariners first visited the shores of Nigeria in 1472. In 1914 they were united in one British colony and on 1 October 1960 Nigeria gained its independence. The 40 years since were marred by a series of coups and a major civil war. The Biafra War broke out in May 1967 when the Ibo-controlled Eastern Regional legislature proclaimed an "independent" republic and took up arms to defend itself. Hundreds of thousands of people were killed in a struggle which, despite support from some African and Western countries, ended in defeat for Biafra in January 1970. Following another abortive attempt at installing a democraticallyelected government in 1993, General Sani Abacha took charge.
In 1995 the execution by the Abacha regime of nine political prisoners, including the renowned writer Ken Saro-Wiwa, led to Nigeria's temporary suspension from the Commonwealth and the imposition of sanctions. Following Abacha's death in 1998, four separate elections culminated in the establishment of local, state and federal governments and the swearing in of Olusegun Obasanjo as president in May 1999. He was re-elected in April 2003. In April 2007, PDP ruling party candidate Umaru Musa Yar'Adua was elected president.