 Vitoria and his disciples engaged in arguments over Spain’s rights in the New World. The debate began when the Dominicans in the Antilles criticized the conquerors’ treatment of indigenous peoples. In a sermon given by the Dominican friar Antonio de Montesinos on December 21, the fourth Sunday of Advent 1511, in Hispaniola (today’s Haiti and Dominican Republic), the Spaniards who attended were told that they lived and died in mortal sin because of the cruelties they had inflicted upon the Amerindians. One of his listeners was Bartolomé de Las Casas (1474–1566), who joined the Dominican order and was converted by Montesinos into the most severe critic of the Conquista (Las Casas 1992).