Irish traditional music has endured more strongly against the forces of cinema, radio and the mass media than the indigenous folk music of most European countries. This was possibly because the country was not a geographical battleground in either of the two World Wars. Another potential factor was that the economy was largely agricultural, where oral tradition usually thrives.
From the end of the Second World War until the late fifties folk music was held in low regard. Comhaltas Ceoltóirí Éireann (an Irish traditional music association) and the popularity of the Fleadh Cheoil (music festival) helped lead the revival of the music. The English Folk music scene also encouraged and gave self-confidence to many Irish musicians. Following the success of The Clancy Brothers and Tommy Makem in the US in 1959, Irish folk music became fashionable again.

The lush sentimental style of singers such as Delia Murphy was replaced by guitar-driven male groups such as The Dubliners. Irish showbands presented a mixture of pop music and folk dance tunes, though these died out during the seventies. The international success of The Chieftains and subsequent musicians and groups has made Irish folk music a global brand.
Historically much old-time music of the USA grew out of the music of Ireland, England and Scotland, as a result of cultural diffusion. By the 1970s Irish traditional music was again influencing music in the US and further afield in Australia and Europe. It has occasionally been fused with rock and roll, punk rock and other genres.

(Wikpedia on Irish Traditional Music)