Bartolomé de las Casas
Dominican friar (1484-1566), former encomendero turned defender of the Indians, whose campaigning shaped the New Laws of 1542 and who faced Juan Ginés de Sepúlveda in the Valladolid debate of 1550-51 — the first great public controversy over the rights of colonized peoples. His polemical statistics are unreliable; his moral argument and influence on law are documented.
Why this wins its question: Las Casas is usually deployed as ammunition — by one side as proof of Spanish atrocity, by the other as proof of Spanish conscience. This object binds both readings to the standard academic monographs and keeps the crown's institutional response (laws, suspension of conquests, the debate itself) at the center, where the scholarship puts it.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
Las Casas, after years as a colonist and encomendero, renounced his holdings and spent five decades campaigning before the Spanish court for the rights of the native peoples of the Americas.
His advocacy contributed directly to the New Laws of 1542, which prohibited the enslavement of Indians and moved to phase out the encomienda system.
In 1550-51 at Valladolid, the crown convoked a formal disputation between Las Casas and Juan Ginés de Sepúlveda on the justice of the conquests and the capacity of the American Indians — while new conquests were officially suspended pending the outcome.
His Brevísima relación (1552) was decisive in forming the anti-Spanish polemical tradition; modern scholarship values it as moral testimony while rejecting its casualty figures as rhetorical exaggeration.
Las Casas matters twice over: as evidence that the empire contained and heard its own radical critics, and as a source whose exaggerated figures fed the later polemical literature against Spain. Hanke's two monographs document both the substance of his advocacy and the crown's extraordinary response — convoking a formal disputation on the justice of the conquests and suspending new conquests while it deliberated. An honest treatment neither discounts his testimony nor treats his numbers as demography.