Waalo was conquered in 1855. Shaykh Umar was defeated at Medina in 1857. The two events marked the real beginning of the partition of Senegambia by the French, the British, and the Portuguese. The process of partition, lasting until the end of the nineteenth century, involved a long series of military campaigns punctuated by lulls and periods of negotiation. As it unfolded, the states and peoples of the region resisted colonial conquest in a variety of ways. The drive toward colonial conquest was fragmented on account of competition between the European powers. The process was therefore jumbled, with piecemeal advances here, uncoordinated thrusts there; hence the artificiality of today's frontiers in the Senegambian region.

Colonial conquest took place against a historical background in which the major economic issues of the first half of the nineteenth century remained essentially unresolved. The heat of military activity, combined with the clash of rival European powers, tended to blur the motives behind the new European drive toward empire that emerged after the mercantilism of the previous centuries. Indeed, the conquest of Senegambia was an integral part of a general context of colonial imperialism in which the dominant concern was the determination of Europe's industrial states to carve up the world.