I agree with others on this thread,'Celtic music' is a concept dreamed up by marketing gurus and any arguements as to what is or isn't 'Celtic' is largely irrelevant. Pre-historians tell us there never was a 'Celtic'race or nation, just a series of tribes or peoples with related languages that at one time stretched across much of northern Europe and were absorbed into more powerful empires like Rome and pushed west by successive incursions of Germanic tribes. A proto-Celtic people probably once lived in the Danube basin and would have spoken a language the ancestor of Irish, Welsh, Cornish, etc, but whatever music they had is long vanished.