I was interested to learn from Malcolm's post of several years ago that the guitar was popular in English and Scottish 'traditional' music in the 18th century. Now consider that there are references to fiddle and banjo sessions from the late 18th/early 19th century in North America, though the guitar was not commonly used in the US together with fiddle and banjo until the early 20th/late 19th(?)century. And now think of the all the music that has been made on both sides of the Atlantic with the guitar-fiddle-banjo line-up during the last 50-75 years. It's almost as though that particular combination was lying around waiting to happen. More evidence of the reciprocal relationship between British-Irish and American folk music.