Between approximately 800 and 1650 the world known to western Europeans was enlarged in a way unparalleled before or since. In the tenth century the Scandinavians reached North America. The high Middle Ages saw Italian traders and missionaries in China, Venetian galleys in ports from Alexandria to Southampton, and German merchants bring the fastnesses of northern Europe into a vital association with the rest of the continent. Then in the fifteenth and sixteenth centuries, in some of the greatest voyages ever made under sail, the Iberians opened the Atlantic and Pacific oceans, subjugating part of the Americas and seizing or obtaining footholds in Africa and Asia. In some cases, as with the Norse in America, settlements soon foundered. In Asia Europeans conquered no more than a few islands, yet established themselves with important economic consequences on the fringes of landmasses whose size and civilizations they only imperfectly understood. But in the Americas whole indigenous societies were destroyed and some parts of the continent brought under European rule in campaigns whose audacity, let alone success, still remains a matter for wonder.