The rapid expansion of European power throughout much of the world in the fifteenth and sixteenth centuries was a matter of wonder at the time, just as its causes have remained a subject of contention ever since. To pious contemporaries it was simply the natural triumph of the True Faith over pagan and infidel. Hernán Cortés, the conqueror of Mexico, wrote of his ‘just war’ against the tyrant Aztec emperor and his people addicted to unspeakable practices. Freedom to navigate the Indian Ocean, maintained João de Barros, the chronicler of Portuguese triumphs, was properly denied by his compatriots to those ignorant of Christianity and Roman Law. More recently, subtler explanations have come into fashion. The penetration by Portugal (with about 1,500,000 inhabitants) of the maritime economy of Asia (sustaining populations of millions), and the destruction by Castile (with a population of about 7,500,000) of the Aztec empire, some 27,000,000 strong, were the victories of superior morale. Europeans, with their will to win, overcame the adherents of stoic, passive and pessimistic religions, or, as M. Chaunu unkindly puts it, quality triumphed over quantity.3 Equally all-embracing is the thesis that meat-eating Iberian warriors had a natural advantage over the troops of civilizations whose grain-based diets were deficient in protein, or that Europeans, with their superior technology-their firearms and their sailing ships mounting artillery— were the predestined winners in any conflict with the less technologically advanced.4 The aim of this paper is to suggest that such arguments have little to commend them, and that European success very largely came from the adept exploitation of conflicts and divisions in indigenous societies, and from the securing of indigenous aid. Such behaviour reflects the pragmatic approach of European commanders in the field, typified by Afonso de Albuquerque, the captor of Goa–future capital of the Estado da India–who there pressed into service all from local dancing girls and musicians to war elephants and mercenaries.5 But such proceedings also reflect the attitudes of an age highly conscious, through resurgent knowledge of the classics, of the virtues of statecraft, just as they reflect, of course, the willingness of some elements in non- European societies to come to terms, for a variety of reasons, with alien intruders.