In the history of the philosophical life of Greece, we have seen (Chapter II.) how important were the influences of maritime discovery and the rise of criticism. Conjointly they closed the Greek Age of Faith. In the life of Europe, at the point we have now reached, they came into action again. [Sidenote: Approach of the Age of Reason.] As on this occasion the circumstances connected with them are numerous and important, I shall consider them separately in this and the following chapter. And, first, of maritime enterprise, which was the harbinger of the Age of Reason in Europe. It gave rise to three great voyages--the discovery of America, the doubling of the Cape, and the circumnavigation of the earth. [Sidenote: State of Mediterranean trade.] At the time of which we are speaking, the commerce of the Mediterranean was chiefly in two directions. The ports of the Black Sea furnished suitable depôts for produce brought down the Tanaïs and other rivers, and for a large portion of the India trade that had come across the Caspian. The seat of this commerce was Genoa. The other direction was the south-east. The shortest course to India was along the Euphrates and the Persian Gulf, but the Red and Arabian seas offered a cheaper and safer route. In the ports of Syria and Egypt were therefore found the larger part of the commodities of India. This trade centred in Venice. A vast development had been given to it through the Crusades, the Venetians probably finding in the transport service of the Holy Wars as great a source of profit as in the India trade. [Sidenote: Rivalry of Genoa and Venice.] Toward the latter part of the fourteenth century it became apparent that the commercial rivalry between Venice and Genoa would terminate to the disadvantage of the latter. The irruption of the Tartars and invasion of the Turks had completely dislocated her Asiatic lines of trade. In the wars between the two republics Genoa had suffered severely. Partly for this reason, and partly through the advantageous treaties that Venice had made with the sultans, giving her the privilege of consulates at Alexandria and Damascus, this republic had at last attained a supremacy over all competitors. The Genoese establishments on the Black Sea had become worthless. [Sidenote: Attempt to reach India by the west.] With ruin before them, and unwilling to yield their Eastern connexions, the merchants of Genoa had tried to retrieve their affairs by war; her practical sailors saw that she might be re-established in another way. There were among them some who were well acquainted with the globular form of the earth, and with what had been done by the Mohammedan astronomers for determining its circumference by the measurement of a degree on the shore of the Red Sea. These men originated the attempt to reach India by sailing to the west.