Letters, Paolo Toscanelli maps and Columbus calculations

This 21st part of the series Popular Science Essays: Correspondence with Toscanelli and sending them maps to Portugal is being questioned by historians. They claim that Toscanelli was not at all a supporter of the Atlantic Ocean expedition. There is only a copy (rewritten by Columbus) of his letter, which says that from Lisbon "to the great and magnificent city of Kinshasa" (Chinese Hangzhou) - 26 times 250 miles, i.e. 6.5 thousand miles. Let's take the old Roman mile at 1481 meters and get the specified distance in kilometres - 9.6 thousand. In fact, from Lisbon to Hangzhou, west in a straight line, not 9.6, but more than 20 thousand km, i.e. more than two times more.In letters sent to the King and Queen of Spain in 1498 and 1503, the Admiral detailed his geographical knowledge, which had developed 15-20 years before. Referring to Ptolemy as well as the medieval theologian and geographer P. d'Ailla, he wrote that the land as a whole was spherical. The second letter (no date) addressed to Columbus contained absolutely no specific information. Toscanelli condescended to "a bold and grandiose plan to sail to eastern countries on the western route". He considered the plan to be the right one and reliable.