Under this intelligent stimulus, Portuguese navigators within a century rounded the Cape of Good Hope, opened the sea route to the Indies, discovered Brazil, circumnavigated the globe, and made Portugal the richest nation in Europe, with a great colonial empire and claims to dominion over half the seas of the world. Portuguese ships carried her flag from Labrador (which reveals its discoverers in its name) and Nova Zembla to the Malay Archipelago and Japan. It is characteristic of the crusading spirit of the age that Prince Henry's first ventures down the African coast were in pursuance of a vague plan to ascend one of the African rivers and unite with the legendary Christian monarch Prester John (Presbyter or Bishop John, whose realm was then supposed to be located in Abyssinia) in a campaign against the Turk. But crusading zeal changed to dreams of wealth when his ships returned from the Senegal coast between 1440 and 1445 with elephants' tusks, gold, and negro slaves. The Gold Coast was already reached; the fabled dangers of equatorial waters--serpent rocks, whirlpools, liquid sun's rays and boiling rivers--were soon proved unreal; and before 1480 the coast well beyond the Congo was known. The continental limits of Africa to southward, long clearly surmised, were verified by the voyage of Bartolomeo Diaz, in 1487. Diaz rounded the cape, sailed northward some 200 miles, and then, troubled by food shortage and heavy weather, turned backward. But he had blazed the trail. The cape he called _Tormentoso_ (tempestuous) was renamed by his sovereign, Joao II, Cape _Bon Esperanto_--the Cape of Goad Hope. The Florentine professor Politian wrote to congratulate the king upon opening to Christianity "new lands, new seas, new worlds, dragged from secular darkness into the light of day."