Irish groups tend to latch on to all kinds (usually good) songs or tunes. Of course, by they time they are passed around and recorded by 6 or 8 Irish groups, they are thought of as "Irish" songs. Tommy Makem and Liam Clancy had a pretty good hit with Bill Staines' "A Place in the Choir". Several groups "stole" it from them and I don't imagine many of them heard Staines' own recordings of it. On the other hand, many recordings have been made of Tommy Makem's "Four Green Fields" and seldom have I seen it credited. It is hard to keep track sometimes.