"There is also speculation that the Portuguese also reached North America before Columbus' expedition that discovered America."
My Portuguese friends says they were cod fishing off newfoundland for centuries earlier.
When Columbus returned from his first voyage, his first port of call was Lisbon. The Portuguese didn't seem surprised by what he had to report, maybe because they knew he knew less than they did. Notice that they got the pope to shift the demarcation line between their claims and those of the Spanish far enough west to include Brazil AND Newfoundland. Regardibng claims, the Portuguese always realized that they were literally out gunned and in general out-resourced by the bigger powers. Just because you get there first is less important than keeping others from making a grab for it. Look at the way that Cabot DID take Newfoundland for England.