Lived: 1494-1573 If Bartolome de Casas was the voice of humanism and concern for the Native Americans, Juan Gines de Sepulveda was the voice of their domination. A Jesuit priest, Sepulveda believed the natives to be natural slaves, not capable of governing themselves. He argued against de Casas at the Valladolid Debate. This debate, organized by King Charles V, was to decide the continued fate of the natives within the Spanish colonial system - continued slavery or emancipation. While Sepulveda lost the debate, and the crown took a position in favor of native freedom, the colonists in the New World ignored to a large extent the King's decree, granting the true victory to Sepulveda.