Northern and southern Nigeria are essentially two different countries, and their histories reflect this disparity. The first recorded empire to flourish in this part of West Africa was Kanem-Borno around Lake Chad, which grew rich from the trans-Saharan trade routes. Islamic states based in the Hausa cities of Kano, Zaria and Nupe also flourished at this time.
Meanwhile, the southwest developed into a patchwork of small states, often dominated by the Yoruba. The Ijebu kingdom rose in the 10th century and constructed the mysterious earthworks at Sungbo's Eredo. Most famously the Benin kingdom became an important centre of trade and produced some of the finest metal artwork in Africa. In the southeast, the Igbo and other agrarian peoples never developed any centralised empires, instead forming loose confederations.
The first contact between Yoruba empires and Europeans was made in the 15th century, when the Portuguese began trading in pepper and, later, slaves. In contrast, the northern Islamic states remained untouched by European influence until well into the 19th century.
In the early 19th century the British took a lead in suppressing slavery along the Niger delta, leading to the annexation of Lagos port – a first colonial toehold. This led to further annexation to thwart the French, who were advancing their territory along the Niger River. By the beginning of the 20th century, British soldiers had advanced as far north as the cities of Kano and Sokoto, where Islamic revivalism had created a rapidly expanding caliphate.
Nigeria was divided in two – the southern, mainly Christian, colony and the northern Islamic protectorate. The British chose to rule indirectly through local kings and chiefs, exacerbating ethnic divisions for political expediency.
The ethnic divisions came back to haunt Nigeria when independence came in October 1960. Politics split along ethnic lines, and in 1966 a group of Igbo army officers staged a coup. General Johnson Ironsi took over as head of state. Another coup quickly followed on its heels, along with massacres of Igbos, which in 1967 provoked civil war by secessionist Igbos.
The war dragged on for three years. Biafra was blockaded, and by the time its forces capitulated in 1970, up to a million Igbos had died, mainly from starvation.
An oil boom smoothed Nigeria's path to national reconciliation, but as the army jockeyed for political control, the next two decades were marked by a series of military coups, with only a brief democratic interlude in the early 1980s. When General Ibrahim Babangida offered elections in 1993, he annulled them when the result appeared to go against him, only to be toppled in a coup soon after by General Sani Abacha.
Abacha was ruthless, purging the army and locking up intellectuals, unionists and pro-democracy activists. His rule reached a nadir in 1995 with the judicial murder of the Ogoni activist Ken Saro-Wiwa, an act that led to Nigeria's expulsion from the Commonwealth.
Salvation finally came in June 1998, in what Nigerians called the 'coup from heaven'. Aged 54, and worth somewhere between US$2 billion and US$5 billion in stolen government money, Abacha died of a heart attack while in the company of two prostitutes. His successor immediately announced elections and in February 1999 Olusegun Obasanjo, a former military leader and ex-president, was returned as president.