Venice, Genoa, and Pisa were now great emporiums of Oriental wares, were waxing rich on a transport trade which had no option but to use their ports and their vessels. Inland Florence had no part in maritime enterprise, but was the manufacturing, literary, and art centre of mediæval Europe. Her silk looms made her famous throughout the world, her banks were the purse of Europe, and among her famous sons were Dante, Petrarch, Boccaccio, Macchiavelli, Michael Angelo, Leonardo da Vinci, Galileo, Amerigo Vespucci. For the development of their commerce, the cities of the North had grouped themselves into the great Hanseatic League, with branches in Bruges, London, Bergen, and Novgorod. Commercialism had everywhere become the keynote of the closing Middle Ages, inspiring that maritime enterprise which was soon to outline a new map of the world. The main route between the West and East had hitherto been by way of the Red Sea and the Euphrates, and it was controlled by the Italian cities. Italy had, therefore, no interest in finding a water route to the East which would rob her of this profitable overland traffic. But the experience of her sailors made them the most skilful of the world's navigators and the readiest instruments of other nations in expeditions of discovery. Thus Columbus of Genoa, Cabot of Venice, and Verrazzano of Florence are found accepting commissions from foreign sovereigns. "The discoveries of Copernicus and Columbus," says Froude, "created, not in any metaphor, but in plain language, a new heaven and a new earth." The new theory of Copernicus was, indeed, one of the choicest flowers of the Renaissance, and though timidly enunciated, it revolutionised the world's geography. Further, the discovery of the polarity of the magnet, and the invention of the astrolabe, gave to the mariners of the fifteenth century a sense of security lacking to their fathers, while the kindling flame of the New Learning led them upon the most daring quests. The Portuguese were the first to enter on the brilliant path of sea-going exploration which distinguishes this century above all others. By 1486 they had already found Table Mountain rising out of the Southern sea, and hoping always for a passage to the East, had named it the Cape of Good Hope. Spain soon followed her rival into these unknown regions, a policy due mainly to the enthusiasm of Isabella of Castile, who, in spite of the conservative apathy of the Council of Salamanca, was eager to become the patroness of Christopher Columbus.