 The depopulation of the Americas, and consequently the shortage of slaves, brought about by diseases brought over by the Europeans as well as slaughter of the native populations, inspired increasing debate during the 16th century over the morality of slavery.The first extensive shipment of black Africans to make good the shortage of native slaves, what would later become known as the Transatlantic slave trade, was initiated at the request of Bishop Las Casas and authorised by Charles V, Holy Roman Emperor in 1517.Las Casas later rejected all forms of unjust slavery and became famous as the great protector of Indian rights.