In 1624, Njinga Mbande, sister of the late sovereign Ngola Mbande, became queen of the Kingdom of Ndongo in southwestern Africa. Two years earlier, she had been baptized under the name Anna de Sousa for political reasons, without fully embracing the Catholic faith. Several years later, the Portuguese resumed their attacks on her kingdom, as they had done during the reigns of her grandfather, father, and brother. Njinga then renounced Catholicism and began seeking alliances against the Portuguese. Initially, she allied with the Imbangala, also known as the Jagas, semi-nomadic warrior groups notorious for their brutal rituals, which included human sacrifices and acts of cannibalism. Njinga joined their ranks, participated in these rites, and led the Imbangala into battle.

Years later, she also allied with the Dutch, the Portuguese's rivals in the region. After decades of warfare, in 1648, Njinga decided to return to diplomacy. Through a few captured Capuchin friars, she attempted to establish contact with the Pope to gain diplomatic support against the Portuguese. It was in this context that she sincerely reapproached the Catholic faith. Njinga miraculously recovered from an illness after reciting Christian prayers, and through conversations with the Capuchin friars, she became convinced that Christianity was the most suitable religion to legitimize the strong, modern monarchy she envisioned.

She subsequently distanced herself from the Imbangala warriors and their rituals, officially reconverted to Catholicism, and in 1656, reached an agreement with the Portuguese. From that moment, she began her efforts to Christianize the Kingdom of Ndongo. Njinga, once again adopting the name Anna, built numerous churches, schools for children, and seminaries for the training of local clergy. She invited many missionaries to her kingdom and promoted the baptism of newborns. The capital city, Kabasa, was renamed Santa Maria of Matamba. Human sacrifices and cannibalism were banned, and many xingula, the local shamans, were arrested or handed over as slaves to the Portuguese.

Njinga also fought against polygamy, which was widespread in the region. She set an example by repudiating her many lovers and concubines and marrying a young Christian man named Sebastiao in a church ceremony. Her greatest triumph came when Pope Alexander VII officially recognized her as the queen of a Christian kingdom in 1661, just two years before her death in 1663.