I believe that Columbus had conceived the idea of sailing westward to the Indies even before he left his home at Savona. My reason is, that his correspondence with Toscanelli on the subject took place in the very year of his arrival in Portugal. That fact alone involves the position that the young weaver had not only become a practical seaman--well versed in all the astronomical knowledge necessary for his profession--a cosmographer, and a draughtsman, but also that he had carefully digested what he had learned, and had formed original conceptions. It seems wonderful that a humble weaver's apprentice could have done all this in the intervals of his regular work. Assuredly it is most wonderful; but I submit that his correspondence with Toscanelli in 1474 proves it to be a fact. We know that there were the means of acquiring such knowledge at Genoa in those days; that city was indeed the center of the nautical science of the day. Benincasa, whose beautiful _Portolani_ may still be seen at the British Museum, and in other collections, was in the height of his fame as a draughtsman at Genoa during the youth of Columbus; so was Pareto. In the workrooms of these famous cartographers the young aspirant would see the most accurate charts that could then be produced, very beautifully executed; and his imagination would be excited by the appearance of all the fabulous islands on the verge of the unknown ocean. When the time arrived for Columbus to leave his home, he naturally chose Lisbon as the point from whence he could best enlarge his experience and mature his plans. Ever since he could remember he had seen the inscriptions respecting members of the Pasagni family, as we may see them now, carved on the white courses of the west front of San Stefano, his parish church. These Genoese Pasagni had been hereditary Admirals of Portugal; they had brought many Genoese seamen to Lisbon; the Cross of St. George marked their exploits on the _Portolani_, and Portugal was thus closely connected with the tradition of Genoese enterprise. So it was to Lisbon that Columbus and his brother made their way, and it was during the ten years of his connection with Portugal that his cosmographical studies, and his ocean voyages from the equator to the arctic circle, _combined with his genius to make Columbus the greatest seaman of his age_.