I do recommend Tim Severin's book on his recreation of the alleged voyage, firstly for their attempts to use period correct construction techniques, and also how the boat itself handled in the Atlantic.<p><a href="https://www.goodreads.com/book/show/1088116.The_Brendan_Voyage" rel="nofollow">https://www.goodreads.com/book/show/1088116.The_Brendan_Voya...</a>
For a good run-down of the various folks that may (or may not) have crossed the Atlantic, see Simon Winchester's book <i>Atlantic</i> (ISBN13: 9780061702587):<p>* <a href="http://www.simonwinchester.com/atlantic" rel="nofollow">http://www.simonwinchester.com/atlantic</a><p>* <a href="https://en.wikipedia.org/wiki/Simon_Winchester" rel="nofollow">https://en.wikipedia.org/wiki/Simon_Winchester</a>
There's a Donald Duck cartoon by Carl Barks called The Golden Helmet that deals with the discovery of America by the Vikings, and then Don Rosa made a follow up that brings up the Celtic theory, among others.<p><a href="https://en.wikipedia.org/wiki/The_Golden_Helmet" rel="nofollow">https://en.wikipedia.org/wiki/The_Golden_Helmet</a>
<a href="https://en.wikipedia.org/wiki/The_Lost_Charts_of_Columbus" rel="nofollow">https://en.wikipedia.org/wiki/The_Lost_Charts_of_Columbus</a>
Probably not, but this stuff is fascinating:<p><a href="https://en.wikipedia.org/wiki/Pre-Columbian_trans-oceanic_contact_theories" rel="nofollow">https://en.wikipedia.org/wiki/Pre-Columbian_trans-oceanic_co...</a>
is this where tolkien got his inspiration for silmarillion? There too, earendil took a quest to find the lost paradise West over the ocean succeeding after many tribulations
Depends on your definition of "discovery". Christopher Columbus's trip to America changed the course of history. Any previous visits by the lost at sea sailors are not important.