The three main contestants for empire in North America had now appeared. Spain, France, and England had all planted their flags upon our shores, although their future struggles were as yet hardly foreshadowed. The fishing grounds, on the high seas and far from the routes of Spain's gold-laden galleons, were open to all, though the English seem early to have established some sort of authority over the rough fishermen of the nations gathered there.[54] The continent itself, however, was merely an unwelcome barrier, save the Spanish possessions in the south, with which, as yet, no other nation had thought of meddling. Nevertheless, a new era had opened, and commerce, which, from the dawn of history, had clung to the Mediterranean, now abandoned that enclosed sea for the open highways of the world's oceans. The Oriental trade began to flow through new channels, and Spain, by the conquest of Mexico, in 1522, tapped unlimited sources of the precious metals. The enormous import business from the East, formerly concentrated in the hands of the great mercantile cities of Italy, passed to the Iberian powers,[55] while men's horizons were widened by the new discoveries, and old established methods, routes, and connections had received severe shocks. The example of Spain and Portugal was making other nations dream of gaining fabulous wealth by finding their way to the riches of the Orient, or gold in the wilds of America. Footnote 54: “The Englishmen, who commonly are lords of the harbors where they fish, and do use all strangers helpe in fishing if need require, accordinge to an old custome of the countrey.” Letter of Anthony Parkhurst, 1578, in Hakluyt, _Voyages_ (Glasgow, 1904), vol. VIII, p. 10. H. P. Biggar states that the English were so heavily interested in the American fisheries by 1522, that the Vice-Admiral sent several men-of-war to the mouth of the Channel to protect the returning vessels. _Early Trading Companies of New France_ (Toronto, 1901), p. 20. Footnote 55: _Cf._ W. Heyd, _Geschichte des Levantehandels in Mittelälter_ (Stuttgart, 1879), vol. II, pp. 514-40. For the next four centuries, the civilization of Europe, which throughout the mediæval period had been hemmed within a narrow region by strong barbaric powers, was able to expand against almost negligible resistance, until, after having encircled the world, it is again faced in our own day by a “closed political system.”[56] At the very moment when new forces were being let loose by the social ferment following the Renaissance and the Reformation, the new lands offered vents through which those forces might in part escape, without causing such explosions as wholly to wreck the social system. Their presence, or, to phrase it differently, the existence of a practically unlimited frontier, during the whole of our colonial period, was one of the great formative elements in our institutions, and in the relations between the colonies and England. Footnote 56: