The work of building up this great domain was largely that of one man, the intrepid Albuquerque. Think what his task was! He was thousands of miles from home and supplies, he had only such forces and munitions as he could bring with him in his little ships, and opposed to him were millions of inhabitants and a multitude of Mohammedan princes. Yet this great captain built up an Indian empire. Portugal at one bound became the greatest trading and colonizing power in the world. Her sources of wealth appeared fabulous, and, like Venice, she made every effort to secure her monopoly. The fleets of other nations were warned that they could not make use of the Cape of Good Hope route, on penalty of being captured or destroyed. Reaching India by Sailing West.--The Earth as a Sphere.--Meanwhile, just as Portugal was carrying to completion her project of reaching India by sailing east, Europe was electrified by the supposed successful attempt of reaching India by sailing directly west, across the Atlantic. This was the plan daringly attempted in 1492 by Christopher Columbus. Columbus was an Italian sailor and cosmographer of Genoa. The idea of sailing west to India did not originate with him, but his is the immortal glory of having persistently sought the means and put the idea into execution. The Portuguese discoveries along the African coast gradually revealed the extension of this continent and the presence of people beyond the equator, and the possibility of passing safely through the tropics. This knowledge was a great stimulus to the peoples of Europe. The geographical theory of the Greeks, that the world is round, was revived. The geographers, however, in making their calculations of the earth's circumference, had fallen into an error of some thousands of miles; that is, instead of finding that it is fully twelve thousand miles from Europe around to the East Indies, they had supposed it about four thousand, or even less. Marco Polo too had exaggerated the distance he had traveled and from his accounts men had been led to believe that China, Japan, and the Spice Islands lie much further to the east than they actually do. By sailing west across one wide ocean, with no intervening lands, it was thought that one could arrive at the island-world off the continent of Asia. This was the theory that was revived in Italy and which clung in men's minds for years and years, even after America was discovered. An Italian, named Toscanelli, drew a map showing how this voyage could be made, and sent Columbus a copy. By sailing first to the Azores, a considerable portion of the journey would be passed, with a convenient resting-stage. Then about thirty-five days' favorable sailing would bring one to the islands of "Cipango," or Japan, which Marco Polo had said lay off the continent of Asia. From here the passage could readily be pursued to Cathay and India.