ports in the Mediterranean, with which this republic traded.  His ambition, however, was not long to be confined to seas so well known.  Scarcely had he attained the age of twenty, when he sailed into the Atlantic; and steering to the north, ran along the coast of Iceland, and, according, to his own journal, penetrated within the arctic circle.  In another voyage he sailed as far south as the Portuguese fort of St. George del Mina, under the equator, on the coast of Africa.  On his return from this voyage, he seems to have engaged in a piratical warfare with the Venetians and Turks, who, at this period, disputed with the Genoese the sovereignty and commerce of the Mediterranean; and in this warfare he was greatly distinguished for enterprize, as well as for cool and undaunted courage.

At this period he was attracted to Lisbon by the fame which Prince Henry had acquired, on account of the encouragement he afforded to maritime discovery.  In this city he married the daughter of a person who had been employed in the earlier navigations of the prince; and from his father-in-law he is said to have obtained possession of a number of journals, sea charts, and other valuable papers.  As he had ascertained that the object of the Portuguese was to reach India by the southern part of Africa, he concluded, that, unless he could devise or suggest some other route, little attention would be paid to him.  He, therefore, turned his thoughts to the practicability of reaching India by sailing to the west.  At this time the rotundity of the earth was generally admitted.  The ancients, whose opinions on the extent and direction of the countries which formed the terrestrial globe, still retained their hold on the minds even of scientific men, had believed that the ocean encompassed the whole earth; the natural and unavoidable conclusion was, that by sailing to the west, India would be reached.  An error of Ptolemy’s, to which we have already adverted, contributed to the belief that this voyage could not be very long; for, according to that geographer, (and his authority was implicitly acceded to,) the space to be sailed over was sixty degrees less than it actually proved to be,—­a space equal to three-fourths, of the Pacific Ocean.  From considering Marco Polo’s account of his travels in the east of Asia, Columbus also derived great encouragement; for, according to him, Cathay and Zepango stretched out to a great extent in an easterly direction; of course they must approach so much the more towards the west of Europe.  It is probable, also, that Columbus flattered himself, that if he did not reach India by a western course, he would, perhaps, discover the Atlantis, which was placed by Plato and Aristotle in the ocean, to the west of Europe.