Complex sentence: The Spanish usually baptized slaves in Africa before embarking them and English law considered baptized Christians exempt from slavery, so these Africans joined about 1,000 English indentured servants already in the colony.
Split into simpler sentences: The Spanish usually baptized slaves in Africa before embarking them. As English law considered baptized Christians exempt from slavery, these Africans joined about 1,000 English indentured servants already in the colony.