The history of Nigeria can be traced to the earliest inhabitants from at least 9000 BC through to 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 Ife Empire, Kingdom of Nri, the Benin Kingdom, and the Oyo Empire. Islam reached Nigeria through the Bornu Empire between 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.