The structures and activity of the international economy probably changed more substantially in the sixteenth century than in the century which followed. In the earlier period the opportunitities offered by a series of remarkable explorations and maritime discoveries progressively altered the volume of commerce and industry, and indeed the general perspectives of the world as then known. Vasco da Gama, during his notable voyage in 1497–8, managed to turn the southern cape of Africa and open a new way to the old riches of the Indies, to the pepper and spices, the silks, cottons and pearls, the perfumes, drugs and other merchandise which through the centuries had largely coloured the conspicuous consumption of Europe. In another direction the frail expedition of Christopher Columbus, touching land in the West Indies in October 1492, led the way for fleets of successors to a fresh continent across the Atlantic. This held forth immense stocks of precious metals and tropical produce, which Europe did not have but was eager to exploit. However, the arrival of these resources—sometimes new, often in abundance—did not find its full explanation in the wavering fortunes of discovery, conquest and plunder. As the new territories grew in stature, they disgorged materials which found their place as commodities in a highly developed market system. Europe received them, not free but at the cost of increased output from her economy. These international outlets came in the wake of territorial conquest and implied expanding export sectors beyond the natural growth of European trade. They helped to widen the outlook on a world of apparently unknown possibilities, encouraging a penchant for intrepid adventure, to which the only limit seemed to be the capacity for enterprise and endeavour. All this contributed collectively a massive human achievement.