This proves that America was known to us in the time of Henry VIII.
So who actually discovered America?
Cabot indeed may have been in Bristol as the letters suggested as he had found an English investor to fund his journey, he had also received a patent from Henry VII. Another group of people in the running for the discovery, are the Scandinavians. When Columbus finally arrived in America the were already people living there, these were the descendants of the Vikings who had landed there between 970 to as late as 1066, Columbus would not have known that so we can see why he is credited.
By far the most interesting candidate is one Abu Raihan al-Biruni, who is being put forward as 'discovering' America without leaving his desk. Biruni was an Islamic scholar born in 973. He studied cartography, mathematics, astronomy, geography and geometry. He had worked out the latitude and longitude of his own town and began to collect similar co-ordinates for other places. Biruni used ancient Greek sources to compile data on hundreds of other places in world and then began adding calculations on other locations from all points of the compass.
If this is fact, then it can be said that he, in theory, discovered America a short time before the Vikings actually set foot in the country.
If any of these contenders for the title of the discovery of America are proven to be fact then Christopher Columbus can still be credited with being the first to initiate regular contact between the peoples of America and Europe.