When playing in an Irish/Celtic band a few years ago the lines became further blurred for me as we did songs out of many different traditons. 'Red-haired Boy' became 'Little Beggar Boy' at the Harp and Fiddle in Pittsburgh, PA. Like blues, rock 'n roll is a combo of celtic and african traditions and clearly defined by Louis Armstrong, "There's only 2 kinds of music, good or bad."