The enthusiasm and confident expectation with which Spain set out to exploit the discoveries of Columbus's first voyage changed to disappointment when subsequent explorations revealed lands of continental dimensions to be sure, but populated by ignorant savages, with no thoroughfare to the ancient civilization and wealth of the East, and no promise of a solid, lucrative commerce such as Portugal had gained. Mines were opened in the West Indies, but it was not until the conquest of Mexico by Cortez (1519-1521) laid open the accumulated wealth of seven centuries that Spain had definite assurance of the treasure which was to pour out of America in a steadily increasing stream. The first two vessels laden with Mexican treasure returned in 1523. Ten years later the exploration and conquest of Peru by Pizarro trebled the influx of silver and gold. The silver mines of Europe were abandoned. The Emperor Charles, as Francis I said, could fight his European campaigns on the wealth of the Indies alone. But between Spain and her "sinews of war" lay 3000 miles of ocean. To hold the colonies themselves, to guard the plate fleets against French, Dutch, and English raiders, to protect her own coastline and maintain communications with her possessions in Italy and the Low Countries, to wage war against the Turk in the Mediterranean, Spain felt the need of a navy. Indeed, in view of these varied motives for maritime strength, it is surprising that Spain depended so largely on impressed merchant vessels, and had made only the beginnings of a royal navy at the time of the Grand Armada.[1] Not primarily a nation of traders or sailors, she had, by grudging assistance to the greatest of sea explorers, fallen into a rich colonial empire, to secure and make the most of which called for sea power. [Footnote 1: "For the kings of England have for many years been at the charge to build and furnish a navy of powerful ships for their own defense, and for the wars only; whereas the French, the Spaniards, the Portugals, and the Hollanders (till of late) have had no proper fleet belonging to their princes or state." Sir Walter Raleigh, A DISCOURSE OF THE INVENTION OF SHIPS.]