Just when we know not, but some time earlier than this, Alfonso V. of Portugal had sought, through the medium of the monk Fernando Martinez (Fernam Martins), to know precisely what was meant by the bruit of Toscanelli's theory of a westward way to India. To an inquiry thus vouched Toscanelli had replied to Fernando Martinez (June 25, 1474), some days before a similar inquiry addressed to Toscanelli reached Florence, from Columbus himself, and through the agency of an aged Florentine merchant settled in Lisbon. It seems probable that no knowledge of Martinez's correspondence with Toscanelli had come to the notice of Columbus; and that the message which the Genoese sent to the Florentine was due simply to the same current rumors of Toscanelli's views which had attracted the attention of the king. So in replying to Columbus Toscanelli simply shortened his task by inclosing, with a brief introduction, a copy of the letter, which he says he had sent "some days before" to Martinez. This letter outlined a plan of western discovery; but it is difficult to establish beyond doubt the exact position which the letter of Toscanelli should hold in the growth of Columbus's views. If Columbus reached Portugal as late as 1473-74, as seems likely, it is rendered less certain that Columbus had grasped his idea anterior to the spread of Toscanelli's theory. In any event, the letter of the Florentine physician would strengthen the growing notions of the Genoese.
As Toscanelli was at this time a man of seventy-seven, and as a belief in the sphericity of the earth was then not unprevalent, and as the theory of a westward way to the East was a necessary concomitant of such views in the minds of thinking men, it can hardly be denied that the latent faith in a westward passage only needed a vigilant mind to develop the theory, and an adventurous spirit to prove its correctness. The development had been found in Toscanelli and the proof was waiting for Columbus,--both Italians; but Humboldt points out how the Florentine very likely thought he was communicating with a Portuguese, when he wrote to Columbus.
This letter has been known since 1571 in the Italian text as given in the _Historie_, which, as it turns out, was inexact and overladen with additions. At least such is the inference when we compare this Italian text with a Latin text, supposed to be the original tongue of the letter, which has been discovered of late years in the handwriting of Columbus himself, on the flyleaf of an Æneas Sylvius (1477), once belonging to Columbus, and still preserved in the Biblioteca Colombina at Seville. The letter which is given in the _Historie_ is accompanied by an antescript, which says that the copy had been sent to Columbus at his request, and that it had been originally addressed to Martinez, some time "before the wars of Castile." How much later than the date June 25, 1474, this copy was sent to Columbus, and when it was received by him, there is no sure means of determining, and it may yet be in itself one of the factors for limiting the range of months during which Columbus must have arrived in Portugal.