He reckoned, fourthly, that as the cosmography of Marinus had given an account of fifteen hours or parts of the circumference of the globe eastwards, and had not yet attained to a knowledge of the eastern extremity of the land, it followed of course that this eastern extremity must be considerably beyond those known limits; and consequently, that the farther it extended eastwards, so much the nearer it must approach to the Cape Verd islands, or the then known western limits of the globe: And, if this space were sea, it might be easily sailed over in a short time; and if land, that it would be much sooner discovered by sailing to the west, since it must be much nearer to these islands in that direction. To this may be added what is related by Strabo in his Fifteenth Book, that no army ever penetrated to the eastern bounds of India, which according to Ctesias is as extensive as all the rest of Asia. Onesicritus affirms that India is a full third part of the world; and Nearchus says that it is four months journey in a straight line from west to east. Pliny, in the 17th Chap, of his 6th Book, says that India is a third part of the earth, and that consequently it must be nearer Spain in the western than in the eastern direction.
The fifth argument which induced the admiral to believe that the distance in a western direction to India was small, was taken from the opinion of Alfragranus and his followers, who computed the circumference of the globe as much less than all other cosmographical writers, as they only allowed 56-2/3 miles to a degree of longitude. Whence my father inferred, that the whole globe being small, the extent of that third part which remained to be discovered must necessarily be proportionally small likewise; and might therefore be sailed over in a short time. And, as the eastern bounds of India were not yet discovered, and must lie considerably nearer us towards the west, he therefore considered that the lands which he might discover in his proposed expedition westwards might properly be denominated the Indies. Hence it appears how much Roderick the archdeacon of Seville was wrong in blaming the admiral for calling those parts the Indies which were not so. But the admiral did not call them the Indies as having been seen or discovered by any other person; but as being in his opinion the eastern part of India beyond the Ganges, to which no cosmographer had ever assigned any precise limits, or made it to border upon any other country farther to the east, considering those unknown parts of eastern India to border on the ocean. And because he believed those countries which he expected to discover formed the eastern and formerly unknown lands of India, and had no appropriate name of their own, he therefore gave them the name of the nearest known country, and called them the West Indies. He was, so much the more induced to choose this appellation that the riches and wealth of India were well known, and he thereby expected the more readily to induce their Catholic Majesties to accede to his proposed undertaking, of the success of which they were doubtful; by saying that he intended to discover the way to India by the west: And he was desirous of being employed in the service of the crown of Castile, in preference to any other.
The second motive which encouraged the admiral to undertake his great enterprize, and which might reasonably induce him to call the countries he proposed to discover by the name of the Indies, was derived from the authority of learned men; who had affirmed that it was possible to sail from the western coast of Africa and Spain to the eastern bounds of India by the westwards, and that the sea which lay between these limits was of no great extent. This is affirmed by Aristotle, in his Second Book of the Heaven and of the World, as explained by Averroes; in which he says that a person may sail from India to Cadiz in a few days. Seneca, in his book of Nature, reflecting upon the knowledge of this world as insignificant in comparison with what shall be attained in a future life, says that a ship may sail in a few days with a fair wind from Spain to India. And if, as some suppose, the same Seneca were the author of the tragedies, he expresses himself to the same purpose in the following chorus of the Medea:
Venient annis Secula feris, quibus Oceanus Vincula rerum laxat, et ingens Pateat tellus, Typhysque novos Detegat orbes, nec sit terris Ultima Thule.
"There will come an age in latter times, when the ocean shall loosen the bonds of things, and a great country shall be discovered; when another Typhys shall find out new worlds, and Thule shall no longer remain the ultimate boundary of the earth."
This prophecy has now certainly been fulfilled by my father. In the first book of his cosmography, Strabo says that the ocean encompasses the whole earth; that in the east it washes the shores of India, and in the west those of Mauritania and Spain; and that if it were not for the vast magnitude of the Atlantic, men might easily sail in a short time from the one to the other upon the same parallel; and he repeats the same opinion in his second book. Pliny, in the Second Book of his Natural History, Chap. iii. says that the ocean surrounds all the earth, and extends from east to west between India and Cadiz. The same author, in his Sixth Book, Chap. xxxi. and Solinus in the sixty-eight chapter of the Remarkable Things of the World, say that, from the islands of the Gorgonides, which are supposed to be those of Cape Verd, it was forty days sail across the Atlantic Ocean to the Hesperides; which islands the admiral concluded were those of the West Indies. Marco Polo the Venetian traveller, and Sir John Mandeville, say that they went much farther eastward than was known to Ptolemy and Marinus. Perhaps these travellers do not mention any eastern sea beyond their discoveries; yet from the accounts which they give of the east, it may be reasonably inferred that India is not far distant from Spain and Africa. Peter Aliacus, in his treatise on the Figure of the Earth, in the eighth Chapter respecting the extent of habitable land, and Julius Capitolinus upon inhabitable places, and in several other treatises, both assert that Spain and India are neighbours towards the west. The latter author, in the nineteenth Chapter of his Cosmography says, according to the opinion of Pliny and other philosophers, the ocean which stretches from the western shores of Spain and Africa to the eastern limits of India is of no great extent, and might certainly be sailed over in a few days with a fair wind; and therefore that the beginning of India eastwards cannot be far distant from the western limits of Africa.
From these and similar authorities of eminent writers, the admiral was led to believe that he had formed a sound opinion on this subject; and he was much encouraged to undertake his proposed voyage of discovery by his contemporary Paul, physician to Signior Dominico of Florence. This Paul corresponded with Ferdinand Lopez, a canon of Lisbon, concerning the voyages which had been undertaken to Guinea in the reign of King Alphonzo of Portugal, and concerning future discoveries which might be made to the westwards. The admiral, who was always exceedingly ardent in inquiries on these topics, came to the knowledge of this correspondence; and soon afterwards, by means of Laurentio Girarde, a Florentine who then resided in Lisbon, entered into correspondence with Paul on this subject, acquainting him with his design, and sending him a small terrestrial globe. The communications from Paul on this subject are as follow:
"To Christopher Columbus, Paul the Physician wisheth health. I perceive the noble and earnest desire which you entertain to sail to those parts which produce spices; and therefore, in answer to your letter, I send you one which I wrote some time ago to a friend of mine, a servant to the king of Portugal, before the wars of Castile, in answer to one he had written to me by the order of his highness upon this same subject; and I send you a sea chart similar to the one I sent to him, which will satisfy your demands. The copy of that letter is this!"