In 1670, the Portuguese were routed at the
Battle of Kitombo by the forces of the
Count of Soyo Estevão da Silva, supported by the Dutch. Meanwhile, pro-Portuguese King Luís was driven from the throne of Kitombo by a rival, Dom António Carrasco, who likewise slaughtered the Portuguese in the settlement. Encouraged by such setbacks, the King of Ndongo, Dom João Hari (Ngola Hari), took the opportunity to revolt against Portuguese suzerainty, cut all communications between Luanda and the Portuguese-allied
Kingdom of Cassanje and attacked Portuguese trade caravans. He dispatched envoys to a number of neighbouring chiefdoms, among them the kingdom of Matamba, seeking to rally them to his cause against the Portuguese. The then Portuguese governor of Angola,
Francisco de Távora, reacted to these events accordingly, requesting reinforcements from
Portuguese Brazil, and quickly dispatching to the Portuguese fort at
Ambaca a small forward contingent under the command of
Luís Lopes de Sequeira, who had previously distinguished himself at the
Battle of Mbwila. Skirmishes between the Portuguese and the forces of Andongo had already taken place before a large Portuguese fleet arrived in Luanda, bringing significant reinforcements from Brazil. At the same time, as many Portuguese soldiers and
Imbangala mercenaries as possible were assembled from the garrisons at Ilamba, Lumbo, Massangano, Cambambe, Muxima and elsewhere. The campaign was to be the largest military campaign the Portuguese had yet undertaken in Angola. ==The siege==