Hi! there's always room for someone to contribute more info, but FYI, there have been a few related posts; check these out for previous discussions on this topic
Could Columbus have known about the Norse voyages to North America?
Did word of the New World discovered by Leif Ericson ever get to the Western Europeans?
Did the rest of Europe know about the Vikings' discovery of America?
How did the Nordic countries react to the 1490-1500s New World discoveries? - i.e. versus what they already knew
Semi-related question: Were there rumours of lands to the west that may have reached explorers?
Wednesday AMA - Piracy from Antiquity to the Present. - re pirate activity impacting trade with the Greenland settlements
Were the Aztecs and Incas explorers? Did they make maps? Did they ever meet? - re possibility of remains washing up in Europe
... more on Basque fishermen