M /rUci of the terrain of the seven Canary Islands is either arid or forbiddingly mountainous. But along Tenerife's northern coast the 5oo-metre line (the altitudinal limit for sugar, wine, and banana cultivation) retreats inland-at Orotava almost 5 kilometres inland. And in the seventeenth century these cramped but fertile mountain slopes, terraced to prevent soil erosion and watered adequately by rainfall and springs, yielded a preponderant share of the entire archipelago's exportable wealth. In i6oo Tenerife accounted for 62 per cent of the total taxes on trade in the Canaries, and its share had grown by i688 to nearly go per cent.1 Likewise, the population of the archipelago was concentrated in Tenerife. One can estimate that the population of the seven islands grew from about 35,000 in I587 to 93,000 in i678 and that over half of the islanders lived in Tenerife at the later date.2 Tenerife's growing population and predominant share of the archipelago's trade resulted in part from geographical advantages, but also from a human victory over geographical obstacles. The prevailing winds and currents made the return voyage to Europe from the Canaries a difficult one for sailing ships. The fleets of Seville's monopoly trade to America, for example, followed the route of Columbus throughout the sixteenth century, stopped at the archipelago on the way west but seldom returned to Seville or Cadiz via the Canaries. The Azores became the Canaries des retours for the American fleets.3 And yet in the sixteenth century the Canarians were already outgrowing their role as mere victuallers of American-bound ships and were tying their export economy to the pulse of older and larger European markets to the north. Hundreds of ships sailed out from Europe to the Canarian ports and then returned north, battling the prevailing north-east winds, withstanding the dark and dirty weather of winter seas, to carry the rich produce of Tenerife to old and established European markets. Tax records, port books, and merchant letters, unexplored in previous studies of the Canarian economy, reveal that this trade was encouraged by the growth