Noah about to be baptised. In medieval Christianity, Noah's three sons were generally considered as the founders of the populations of the three known continents, Japheth/Europe, Shem/Asia, and Ham/Africa, although a rarer variation held that they represented the three classes of medieval society – the priests (Shem), the warriors (Japheth), and the peasants (Ham). In medieval Christian thought, Ham was considered to be the ancestor of the people of black Africa. So, in racialist arguments, the curse of Ham became a justification for the slavery of the black races. Isaac Newton, in his religious works on the development of religion, wrote
Criticism of Christianity Canaan be the slave of Shem." which was interpreted to mean that Africans were the descendants of Ham, cursed with "the mark of Ham" to be servants to the descendants of Japheth (Europeans) and Shem (Asians). In 1452, Pope Nicholas V instituted the hereditary slavery of captured Muslims and pagans, regarding all non-Christians as "enemies of Christ." The ""Curse of Ham"" along with Paul's Epistle to the Ephesians, VI, 5-7 helped American slaveowners to balance their beliefs with slavery. There are plenty other pro-slavery verses in the Old Testament that were often quoted. New Testament was ignored except that reminding