The mansa kept a large standing army and the battalion commanders were among the more important officials at the royal court. Each army battalion consisted of a small elite corps of horsemen and a large body of foot soldiers armed with bows and spears. The army was used to protect the empire from outside attack, patrol trading routes and to ensure district chiefs paid their tribute to the king. (from History of Africa 3rd edition by Kevin Shillington p.103)
The Spirits of the Land 