Las Casas quickly evangelized the serfs on his land, and, in either 1512 or 1513, he became a priest. On August 15, 1514, Las Casas delivered a now-famous sermon declaring his intent to return the serfs to the governor of the West Indies. Las Casas thenceforth advocated for better treatment of the American Indians.
Why were de la Casas arguments important?
Las Casas sought to change the methods of the Spanish conquest, and believed that both the Spaniards and indigenous communities could build a new civilization in America together. For this reason, during his stay in Spain he conceived the Plan para la reformación de las Indias (Plan for the Reformation of the Indies).
While the Pope had granted Spain sovereignty over the New World, de Las Casas argued that the property rights and rights to their own labor still belonged to the native peoples. Natives were subjects of the Spanish crown, and to treat them as less than human violated the laws of God, nature, and Spain.
Bartolomé de Las Casas was a Dominican priest who was one of the first Spanish settlers in the New World. After participating in the conquest of Cuba, Las Casas freed his own slaves and spoke out against Spanish cruelties and injustices in the empire.
Bartolomé de Las Casas, (born 1474 or 1484, Sevilla?, Spain—died July 1566, Madrid), early Spanish historian and Dominican missionary who was the first to expose the oppression of indigenous peoples by Europeans in the Americas and to call for the abolition of slavery there.
Until his death, Bartolomé de las Casas, worked tirelessly to prevent the enslavement of all native people and later regretted wholeheartedly his advocacy of African slavery.
Sepulveda argued against Las Casas on behalf of the colonists’ property rights. Sepulveda rationalized Spanish treatment of American Indians by arguing that Indians were “natural slaves” and that Spanish presence in the New World would benefit them.
He was also known as the greatest advocate for justice for the indigenous peoples and defended them and their freedoms in the most celebrated debate of the sixteenth century called by the Emperor Charles V to determine the justice and legitimacy of the Conquest.