New Worlds and Th eir Challenges 93works of Aquinas. He had connections in prominent humanist circles, be-
ing a personal friend of the noted Spanish humanist Luis de Vives and a
defender of the famous scholar and polemicist Erasmus of Rotterdam from
attacks by conservatives.
Vitoria was very impressed by the stories related by Valverde— though
not in the manner intended. He was shocked by what he heard, and the
more that he learned about the conduct of the Spanish in the New World,
the more horrifi ed he became. Later in 1534, he wrote in a private letter that
“no business shocks me or embarrasses me more than the corrupt profi ts
and aff airs of the Indies. Th eir very mention freezes the blood in my veins.”
In 1539, he went public with his concerns, delivering a memorable set of
lectures, known as a “relection,” entitled De Indis (On the American Indi-
ans). In these, he discussed various issues largely from the standpoint of
natural law and just- war doctrine. Vitoria’s conclusions, in some ways, were
not so radical. He did accept that, in principle, the Spanish might have had
some just cause for war against the Indians. But he doubted whether that
amounted to a right of outright conquest and annexation of the Indian
realms.
Questions of relations with peoples outside the Christian fold were, to be
sure, nothing new in the sixteenth century. Eu rope had never been a closed
world. Th roughout the Middle Ages, from the seventh century onward, the
Eu ro pe an states had had to contend with a powerful and advanced civiliza-
tion armed with a new religion, Islam. If the principles of natural law were
truly universal, as claimed, then somehow a place would have to be found
within its framework for the role of non- Christian peoples. Islamic society
faced the same challenge, since its religion, too, was a universal one. But
Muslims and Christians took signifi cantly diff erent approaches to many of
the international legal issues of the time.
Th e greatest challenges arose when Eu ro pe an explorers encountered soci-
eties, in Africa and the New World, with which they had had no prior con-
tact of any kind. Dilemmas confronted by Spain in the Americas were the
most conspicuous of these. Not without reason has this era been termed the
“Spanish age” of international law. But even if the most prominent actors of
the period were Spanish, the many contributions that they made to the de-
velopment of international law belong to the world at large.