The history of Nigeria can be traced to the earliest inhabitants whose date remains at least 13,000 BC through the early civilizations such as the Nok culture which began around 1500 BC. Numerous ancient African civilizations settled in the region that is known today as Nigeria, such as the Kingdom of Nri, the Benin Kingdom, and the Oyo Empire. Islam reached Nigeria through the Bornu Empire between (1068 AD) and Hausa Kingdom during the 11th century, while Christianity came to Nigeria in the 15th century through Augustinian and Capuchin monks from Portugal to the Kingdom of Warri. The Songhai Empire also occupied part of the region. Through contact with Europeans, early harbour towns such as Calabar, Badagry, and Bonny emerged along the coast after 1480, which did business in the transatlantic slave trade, among other things. Conflicts in the hinterland, such as the civil war in the Oyo Empire, meant that new enslaved people were constantly being "supplied".
After 1804, Usman dan Fodio unified an immense territory in his jihad against the superior but quarrelling Hausa states of the north, which was stabilised by his successors as the "Caliphate of Sokoto".