In his day, as we have seen, Portugal was the centre of geographical knowledge, and he and his brother Bartolomeo, after many voyages north and south, settled at last in Lisbon--his brother as a map-maker, and himself as a practical seaman.

This was about the year 1473, and shortly afterwards he married Felipa Moniz, daughter of Bartolomeo Perestrello, an Italian in the service of the King of Portugal, and for some time Governor of Madeira.
Now it chanced just at this time that there was a rumour in Portugal that a certain Italian philosopher, named Toscanelli, had put forth views as to the possibility of a westward voyage to Cathay, or China, and the Portuguese king had, through a monk named Martinez, applied to Toscanelli to know his views, which were given in a letter dated 25th June 1474.

It would appear that, quite independently, Columbus had heard the rumour, and applied to Toscanelli, for in the latter's reply he, like a good business man, shortened his answer by giving a copy of the letter he had recently written to Martinez.

What was more important and more useful, Toscanelli sent a map showing in hours (or degrees) the probable distance between Spain and Cathay westward.

By adding the information given by Marco Polo to the incorrect views of Ptolemy about the breadth of the inhabited world, Toscanelli reduced the distance from the Azores to 52 deg., or 3120 miles.