I don't know if he was really influential, and I'd think it unlikely that this is the reason for the popularity of Irish traditional tunes (they were, after all, in vogue at the time of Queen Elizabeth I).

It is true, though, that a man named W. H. Grattan Flood wrote "A History of Irish Music" in 1904. This book seems to claim that every tune ever invented was Irish. I have a copy, and it's hilarious.

:-)