a cosmic observer, privileged to look down on the world of the fifteenth century from a commanding height, would have noticed a number of cultures and civilisations separated by great distances, poor communications and, in some cases, mutual ignorance or lack of interest. He might, however, have detected – in places, for the most part, outside Latin Christendom – some stirrings at the edges: the dilation of political frontiers or the beginnings of movements of expansion, of settlement, trade, conquest and proselytisation, which would make the world of the next few centuries an arena of imperial competition where expanding civilisations collided and where virtually all human communities were joined in conflict, commerce and contagion. The accomplishment of this enormous and conspicuous change depended on the creation of practical routes of access between previously isolated or barely-communicating groups of people.

In these pages, ‘exploration’ is understood to mean the identification, investigation and recording of such routes. The process came to be dominated by explorers from Latin Christendom. Yet our hypothetical observer, unless also endowed with foresight, would probably not have been able to predict such an outcome until the century was well advanced. Such sources of motivation as material exigency, scientific curiosity, missionary zeal, commercial spirit or wanton aggression were not peculiar to any one part of the world, and, compared with China and Islam, Latin Christendom was underequipped in the technical resources with which to undertake long journeys, to sustain life during them, to find directions in unfamiliar places, to record and communicate the information gathered.