By this means the Indian Ocean became, for all trade purposes, a Portuguese lake throughout the sixteenth century, as will be seen from the preceding map, showing the trading stations of the Portuguese all along the shores of the ocean. But they only possessed their monopoly for fifty years, for in 1580 the Spanish and Portuguese crowns became united on the head of Philip II., and by the time Portugal recovered its independence, in 1640, serious rivals had arisen to compete with her and Spain for the monopoly of the Eastern trade.
[Authorities: Major, Prince Henry the Navigator, 1869; Beazeley, Prince Henry the Navigator, 1895; F. Hummerich, Vasco da Gama, 1896.]
CHAPTER VII.
TO THE INDIES WESTWARD—THE SPANISH ROUTE—COLUMBUS AND MAGELLAN.
While the Portuguese had, with slow persistency, devoted nearly a century to carrying out Prince Henry's idea of reaching the Indies by the eastward route, a bold yet simple idea had seized upon a Genoese sailor, which was intended to achieve the same purpose by sailing westward. The ancients, as we have seen, had recognised the rotundity of the earth, and Eratosthenes had even recognised the possibility of reaching India by sailing westward. Certain traditions of the Greeks and the Irish had placed mysterious islands far out to the west in the Atlantic, and the great philosopher Plato had imag-
