The Spanish theologian and political theorist Francisco de Vitoria (ca. 1483-1546) was the first great theorist of modern international law. He provided an updated, if uneasy, justification for Spain's conquests in the New World.

Little is known of the early life of Francisco de Vitoria. He studied at Burgos and taught at the universities of Valladolid (1523-1526) and of Salamanca. At the latter institution, in 1539, he delivered his famous lectures on law, war, and the New World, eventually published as De Indis et de jure belli relectiones (On the Indians and the Law of War).

As a Dominican friar, Vitoria was deeply involved with the teachings on theology and politics of his great predecessor St. Thomas Aquinas. Yet there were worlds of difference between the Mediterranean-centered civilization of the 13th-century Angelic Doctor and the ocean-spanning Hapsburg Empire of Vitoria's day. Vitoria and his colleagues at Salamanca undertook to reconcile these differences with established doctrine. Their success produced a body of theoretical legal principles for the age of European imperialism and the nation-state.

By 1539 Spain (then part of the Hapsburg Empire) was well entrenched in the Americas--but old doubts about its exercise of sovereignty persisted. Vitoria, in effect, revised the medieval doctrines (derived in part from Roman law) on the laws of God, nature, and nations. In brief, these doctrines stated that God's law, known only in full to Him, could be apprehended by humanity, in part, through divine revelation and through right reason. By means of the latter, men could discover those practices that were universally just. They were then gradually incorporated into customary law or framed by the just ruler as positive law. The law of nations allowed different peoples to live together under the same ruler; it also retained what was left of the spontaneous, natural law relations between individuals after they had passed out of the "state of nature" into political life.

Vitoria adapted the doctrine of the law of nature to the new conditions. The law of nature became a public law that regulated relations between territorial states, which, because of their sovereign status, resembled the sovereign individuals of the prepolitical "state of nature." The law of nature regulated their relations, irrespective of their religious or political convictions; and this law, now called international law, applied to the conduct of and grounds for war as well. Although the pope continued to exercise a spiritual dominion over Christendom, Christendom was no longer the whole world--which was now seen to be divided among legally independent states. With this formula, Vitoria laid to rest the political universalism of the Middle Ages; and he denied the superior right of Christian princes to conquer and rule over remote heathen peoples by virtue of the latters' religious "errors."

Vitoria, however, upheld the pope's authority to entrust one Christian power with the task of converting the heathen. He also included among the rights of nations the right to enter into trade relations and to export missionaries for peaceful evangelical work. Moreover, if the state to which these benign and pacific agents were dispatched forcefully repelled or mistreated them in any way, these measures could constitute grounds for just war, conquest, and subsequent administration of the offending state. Finally, said Vitoria, such administration should take the form of a guardianship concerned with the material--and, above all, spiritual--welfare of the conquered peoples.

Initial hostility to Vitoria's views eventually gave way to recognition of their utility and to their partial incorporation into Spanish imperial law. Vitoria died in Salamanca on Aug. 12, 1546.

Further Reading

• Vitoria's Latin texts appear as volume 7 of the series Classics of International Law (1917). Three books by J. H. Parry provide the intellectual and historical setting: The Spanish Theory of Empire (1940), The Age of Reconnaissance (1963), and The Spanish Seaborne Empire (1966). Vitoria's place in the history of Spanish and European thought is evaluated in Friedrich Heer, The Intellectual History of Europe, vol. 2 (1968), and in Frederick Copleston, A History of Philosophy, vol. 3, pt. 2 (1963).