If the world was round, as the sun and moon were, and as so many men of learning believed, India or the Indies must be to the west of Portugal.
The value of direct trade with the Indies would be enormous.

Europe had already acquired a taste for the spices of India and had confidence in the drugs of India.

The silks and other articles of clothing made in India, and the carpets of India, were well known and prized.

Marco Polo and others had given an impression that there was much gold in India; and the pearls and precious stones of India excited the imagination of all who read his travels.
The immense value of such a commerce may be estimated from one fact.
When, a generation after this time, one ship only of all the squadron of Magellan returned to Cadiz, after the first voyage round the world, she was loaded with spices from the Moluccas.

These spices were sold by the Spanish government for so large a sum of money that the king was remunerated for the whole cost of the expedition, and even made a very large profit from a transaction which had cost a great deal in its outfit.
Columbus was able, therefore, to offer mercantile adventurers the promise of great profit in case of success; and at this time kings were willing to take their share of such profits as might accrue.
The letter of Toscanelli, the Italian geographer, which has been spoken of, was addressed to Alphonso V, the King of Portugal.