Some african slaves brought Christianity with them to the new world

We know that the Congo was Catholic before the slave trade and that slaves were taken from the Congo (not just those sold by the Kongo King to the Portuguese). So we have to assume that there were African Catholic Slaves sent to the Caribbean. Here is what Wikipedia has to say:

Mvemba a Nzinga or Nzinga Mbemba (c. 1456 – 1542 or 1543), also known as King Afonso I, was a ruler of the Kingdom of Kongo in the first half of the 16th century. Afonso is best known for his vigorous attempt to convert Kongo to a Catholic country, by establishing the Roman Catholic Church in Kongo, providing for its financing from tax revenues, and creating schools. By 1516 there were over 1000 students in the royal school, and other schools were located in the provinces, eventually resulting in the development of a fully literate noble class (schools were not built for ordinary people). Afonso also sought to develop an appropriate theology to merge the religious traditions of his own country with that of Christianity. He studied theological textbooks, falling asleep over them, according to Rui de Aguiar (the Portuguese royal chaplain who was sent to assist him). To aid in this task, Afonso sent various of his children and nobles to Europe to study, including his son Henrique Kinu a Mvemba, who was elevated to the status of bishop in 1518. He was given the bishopric of Utica (in North Africa) by the Vatican, but actually served in Kongo from his return there in the early 1520s until his death in 1531.


The Kingdom of Kongo became a major source of slaves for Portuguese traders and other European powers. The Cantino Atlas of 1502 mentions Kongo as a source of slaves for the island of São Tomé. Slavery had existed in Kongo long before the arrival of the Portuguese, and Afonso's early letters show the evidence of slave markets. They also show the purchase and sale of slaves within the country and his accounts on capturing slaves in war which were given and sold to Portuguese merchants. It is likely that most of the slaves exported to the Portuguese were war captives from Kongo's campaigns of expansion. In addition, the slaving wars helped Afonso consolidate his power in southern and eastern border regions.


Despite its long establishment within his kingdom, Afonso believed that the slave trade should be subject to Kongo law. When he suspected the Portuguese of receiving illegally enslaved persons to sell, he wrote to King João III of Portugal in 1526 imploring him to put a stop to the practice. Ultimately, Afonso decided to establish a special committee to determine the legality of the enslavement of those who were being sold.