On the American Indians (De Indis)

A public lecture, or relectio, given at the University of Salamanca in 1539 by the Dominican theologian Francisco de Vitoria, and printed after his death. It asks by what right the Spanish came to rule the peoples of the Americas. The first part argues that before the Spanish arrived the Indians were true owners of their lands and true rulers, public and private: neither sin nor unbelief nor alleged lack of reason takes away dominion. The second part rejects the common justifications for conquest one by one: that the emperor is lord of the world, that the pope holds temporal power over unbelievers, that the lands were discovered, that the Indians refused the faith or committed sins against nature. The third part sets out titles Vitoria thought could be legitimate, starting from a natural right of all peoples to travel, trade and preach, and including the protection of innocent victims. Critics note that these titles could still be used to justify conquest.

It is a founding text of international law and of argument about the rights of colonised peoples, and it shows how scholastic natural law met the hardest political question of its century.