The earliest inhabitants of Cameroon were probably the Baka (Pygmies). They still inhabit the forests of the south and east provinces. Bantu speakers originating in the Cameroonian highlands were among the first groups to move out before other invaders. The Mandara kingdom in the Mandara Mountains was founded around 1500 and erected fortified structures, the purpose and exact history of which are still unresolved. The Aro Confederacy of Nigeria had presence in western (later called British) Cameroon due to trade and migration in the 18th and 19th centuries.
During the late 1770s and the early 19th century, the Fulani, a pastoral Islamic people of the western Sahel, conquered most of what is now northern Cameroon, subjugating or displacing its largely non-Muslim inhabitants.
Although the Portuguese arrived on Cameroon’s doorstep in the 16th century, malaria prevented significant European settlement and conquest of the interior until the late 1870s, when large supplies of the malaria suppressant, quinine, became available. The early European presence in Cameroon was primarily devoted to coastal trade and the acquisition of slaves. The northern part of Cameroon was an important part of the Muslim slave trade network. The slave trade was largely suppressed by the mid-19th century. Christian missions established a presence in the late 19th century and continue to play a role in Cameroonian life.