This article introduces the key issues and scope of the 16th-century debate over the rights of the native American peoples encountered by Columbus and the Castilian conquistadores. The historic attempt by theologians and missionaries to limit imperial expansion and to defend the dignity of conquered peoples is an example of Western self-criticism and a fundamental contribution of the Catholic Church to the slow emergence of human rights discourses. This article then focuses on the first pages of Bartolomé de Las Casas’s Short Account of the Destruction of the Indies, a text that played a pivotal role in the formation of the Black Legend against Spain, but also in the drafting of the Leyes Nuevas (New Laws) of 1542. While the Short Account’s hyperbolic and explosive prose are well-known, its religious roots can be detected in the prologue and preface, with their discussion of biblical kingship, virtuous Indians, mortal sin, and (un)Christian behavior.