International relations in pre-colonial West Africa were conducted in accordance with customary law, which exhibited broadly similar characteristics over a wide area. Trade and politics, linking the coast, the forest and the savannah, led to the development of diplomacy in the more centrally-organized states. Inter-African embassies enjoyed a degree of prestige and immunity comparable to that which protected European diplomacy, and a widely accepted protocol regulated negotiations. Treaties were concluded solemnly and sanctions were provided for their observance. Embassies were also sent to Europe and adjacent European possessions and settlements, North Africa and the Near East, and were generally received on a proper footing.
The indigenous system of international relations was affected by two major external influences. The first, that of Islam, notably contributed literacy, and led in the Islamized states and in Ashanti to the evolution of chanceries. It also introduced the distinction in international law and practice between Muslims and non-Muslims. The Muslim states exchanged embassies, Bornu, for example, maintaining intermittent relations with North Africa and Istanbul for three centuries. The second influence, that of Western Europe, spread the knowledge of European languages which, like Arabic, facilitated communication between West Africans themselves as well as with outsiders. The development of the resident embassy in sixteenth-century Europe was apparently not reflected in West Africa until the nineteenth century, but approximations to the system of continuous diplomacy did arise, probably independently. Diplomatic relations with both Muslims and Europeans tended to increase the influence in West African politics and society of the literate élite.
The indigenous system of international relations in West Africa was flexible and effective, and it seems that it was not so much diplomatic as military incapacity which allowed the Muslims to overthrow governments there and the Europeans to partition the region.