I'm not sure exactly when they started performing (it was after 1955 whne Liam and Tommy M. emigrated to the U.S.). But they were most definately performing and recording before 1960. Since the Beatles became successful themselves in 61 or so, obviously the Clancy's were not influenced by the Beatles early on. Possibly there was a connection with the skiffle craze - which only had a limited run in the U.S. - but who knows.