During the fifteenth and sixteenth centuries, Bornu was a major expansionist power, and warfare was the main function of the state. According to historian Ronald Cohen,

as many as seven or eight military campaigns a year were not uncommon; this meant an expedition, might leave Bornu every six or eight weeks during the dry season. With so much militarism the techniques of warfare elaborated accordingly. From at least the sixteenth century onward, Bornu imported muskets, swords, and chain-mail, which were vital and ancient parts of the Saharan trade, although such armaments were also manufactured by Bornu craftsmen as well.

The army itself was organized into regiments, representing a local area or an, ethnic group under their own leaders, and they went into battle according to a welllaid- but military strategy Campaigns were almost always conducted against walled towns. The shield bearers...