In the story of course, Brendan does in the end reach a continent. He travels inland in a lovely verdant land for 40 days, and reaches the bank of a mighty river flowing westward, onward, but there meets a young man who gives him a poor report of things, so he returns to the coast and sails back to Ireland.
The coins of Bar-Kokhba were considered unclean and Jews were ordered to destroy them, and the Temple he established is not counted, ie the Second Temple was destroyed in AD 70, but the one to come soon is the Third Temple, not the Fourth, since Bar-Kokhba is not in good odour even yet.
Anyway, as a result, more than half of the Bar Kokhba coins found in the world have been found in Tennessee, Kentucky, and Georgia. These people probably fled Jerusalem and Betar so early, that they never learned of the rabbinical orders to destroy them.
The pioneer American Scots-Irish farmers who found the coins could hardly have faked them; a few diehards did come here.