The 1550 hearing at Valladolid, ordered by the Spanish crown, in which two scholars argued whether the indigenous peoples of the Americas were rational beings with legitimate societies or natural inferiors whom Spain could justly conquer. Bartolomé de las Casas held they were fully human, to be won only by peaceful persuasion; Juan Ginés de Sepúlveda, invoking Aristotle’s idea of natural slavery, argued that their barbarism made conquest a lesser evil. No verdict was delivered and the conquest continued — but it is remembered as one of the first times a European power formally interrogated its own right to subjugate another people.
In 1550 an empire stopped, for a moment, to ask a question that empires almost never ask out loud: by what right do we do this? Troubled by reports of slaughter and enslavement, the Spanish crown suspended its conquests in the Americas and ordered a panel of learned men to settle a matter of conscience. Were the peoples of the New World rational communities with legitimate rulers and rights of their own, or were they barbarians whose practices justified the Spaniards in conquering and ruling them? Two men were called to argue it. One had crossed the ocean and seen the killing with his own eyes. The other had read his Aristotle and never left Spain. Their dispute reached no clear winner, and the killing went on. But the question had been spoken inside the machinery of empire, and it could not be wholly unspoken again.