Other than the Norse, are there any credible candidates for transatlantic contact pre-Columbus? I don't mean vague myths like Saint Brendan, but more like the anecdotes we have in my home city of Bristol that when John Cabot left here for Newfoundland in 1497 there were sailors with him who'd been crossing the Atlantic for decades. Is there any truth, or even a chance of any truth, in stories such as this?