The document discusses the origins and justification of the Portuguese slave trade in the 15th century. It summarizes that Portuguese merchants began capturing slaves on the west coast of Africa due to the economic potential. Pope Nicolas V issued papal bulls in 1452 and 1455 that granted Portugal the right to enslave sub-Saharan Africans, arguing it would Christianize "barbarous" pagans. The Pope instructed the Portuguese king to invade, capture, and subjugate pagans and enemies of Christ and reduce them to perpetual slavery.