The idea, then, which Columbus claimed as exclusively his own was conveyed to him by Toscanelli—or, at least, it so appears—and Toscanelli obtained it from the ancients. For, says one having authority, "Eratosthenes, accepting the spherical theory, had advanced the identical notion which nearly seventeen hundred years later impelled Columbus to his voyage. He held the known world to span one-third of the circuit of the globe, as Strabo did at a later day, leaving an unknown two-thirds of sea; and if it were not that the vast extent of the Atlantic Sea rendered it impossible, one might even sail from the coast of Spain to that of India, along the same parallel."
And again: "An important element in the problem was the statement of Marco Polo regarding a large island, which he called Cipango, and which he represented as lying in the ocean off the eastern coast of Asia. This carried the eastern verge of the Asiatic world farther than the ancients had known, and, on the spherical theory, brought land nearer westward from Europe than could earlier have been supposed.... Humboldt has pointed out that neither Christopher Columbus nor his son Ferdinand mentions Marco Polo; still, we know that the former had read his book."[5]
FOOTNOTES:
[4] Justin Winsor, in The Narrative and Critical History of America.
[5] Narrative and Critical History of America.