Two Catholic moralists of Spain's
siglo de oro, Francisco de Vitoria (1483-1546) and Domingo de Soto (1494-1560), examined the condition of the Indians of the New World. Using the theological system of Saint Thomas Aquinas (1225-1274), they attacked the excesses of the
conquistadores but concluded that slavery was justifiable under some circumstances. This study compares and contrasts their adapted notion of the critical concepts of «right» and «dominion» with the original perspective of Aquinas.