Maria de Fonseca was the great wife of Msiri, the powerful warrior-king of Katanga, at the time when the Stairs Expedition arrived in 1891 to take possession of the territory for the Belgian King Leopold II, with or without Msiri's consent. Msiri typically cemented alliances with trading partners by marriage. Maria was the daughter of mixed Portuguese-African parents from Angola, and was also the sister of Coimbra, the first trader to supply him with gunpowder from the west coast, the key to Msiri's power.