Early modern Europe emerged from its isolation and localism during the Middle Ages by conquering the world’s oceans--opening direct contact and commerce with Africa and Asia and rediscovering America. Before the end of the fourteenth century, western Europeans had relied on the mariners and merchants of the Muslim world for their access to the trade and technology of Africa and Asia. But during the fifteenth century, western Europeans mastered the sea, carved out new sea routes to Africa and Asia, and laid claim to the Americas. The results of those efforts at exploration and discovery transformed western Europe from a backward society into a major world power.

The story of European exploration and discovery in the fifteenth and sixteenth centuries starts with the international fishing community off Newfoundland. The tales traded by these ordinary seamen and traders featured the Portuguese explorations of the coast of Africa and their charting of a new route to Asia, the efforts of John Cabot to find a northwest passage to the Orient; and, of course, Columbus’s discovery of America.

Encounters with the Americas occurred because of Europeans’ conquest of the high seas, which in turn was part of a larger technological, economic, demographic, and cultural transformation. The outward reach began with the successful voyages of the Portuguese into the Atlantic in the late 1300s. By the early 1400s they had established sugar plantations on the Atlantic islands worked by enslaved Africans. The Portuguese also initiated a trade with West Africa. By the end of the century their explorers had rounded the tip of that continent and opened a direct commerce with India.

The Spanish laid claim to the Americas, led by the discovery of an Italian mariner, Christopher Columbus.

Asian migrants crossed the Bering Strait to Alaska many millennia before 1492. When Europeans first arrived in the Americas, these Indian cultures were numerous and diverse.

The Aztec economy and society encountered by Spanish explorers was similar in some respects to that of sixteenth-century Europe. One crucial difference, however, was that Aztec expansionism did not take the form of exploration and colonization across the seas.

Conditions in late medieval Europe bred a sense of crisis mixed with a sense of possibility. Life was uncertain and often violent. The economic and political evolution concentrated investment capital in the hands of merchants, financiers, and landlords. Population growth put pressure on a limited supply of land. Political authority became concentrated in nation-states. All these changes, coupled with advances in maritime technology, allowed Europeans to push back the ocean frontier and to support overseas settlement.

Spain took the lead in exploring and colonizing the Americas. Conquistadors like Hernando Cortes supplanted native societies as the new overlords of Central and South America. Technological superiority, divisions within Indian empires, and the devastation of native populations by European diseases made the Spanish conquest easier.

Spanish monarchs replaced the conquistadors with their own rule, through an elaborate civil and ecclesiastical bureaucracy. The empire that developed in the sixteenth century rested largely on the coerced labor of natives and imported Africans. It proved enormously profitable. That wealth, in turn, made Spain the dominant power in Europe.

While Catholic Spain developed its American empire, the Protestant Reformation transformed western Europe, and added a new dimension to the ensuing competition for empire. Protestant reformers criticized the nature and teachings of the Roman Catholic Church. They said that men and women were saved not by good works but through divine grace alone. Protestants also stressed the ability of each individual to read and understand the will of God as revealed in the Bible. By the reign of Elizabeth, Protestantism was established in England, although an impatient minority wanted to "purify" it further.

Protestant attacks on Roman Catholicism won both zealous followers and determined opponents, triggering a series of bloody religious wars. Young Englishmen found adventure in these religious conflicts, as well as in England’s effort to conquer and colonize Ireland.

Many veterans of the Irish campaigns turned their attention to North America in the 1570s and 1580s. The threat Spain posed to English economic and military security encouraged Elizabeth I to challenge Spain more aggressively. English merchants and gentlemen, in search of new markets and new land, lent increasing support to colonization schemes as well. A series of failed efforts at colonization paved the way for renewed English expansionism in the seventeenth century.