Well Will, you have funny sessions if someone's playing the canon! Not been in one like that since 1812, the bodhran is quite loud enough for me.

But Sirius Lee.

Let's say, everyone has been playing a tune for yonks, say Bonny Green Garters. Then you find out it was composed by, say Beethoven*. Does the canon need to be reloaded?

I think this kicks the (c) into touch. It means there can't BE a canon until someone has done all the research, and even then someone might come up with a mediaeval manuscript that shows Soldier's Joy (c) 1150 Abbess Hildegard of Bingen.

Perhaps the process of what happens to a tune or song can be more important than its composition? The fact that many of our best traditional songs can be shown to have been reworked from bits and pieces by 18th or 19th century hack balladeers doesn't make them worth less as songs, and the process of refinement and reinterpretation over the years has polished them into powerful works of art. Evolution is perhaps as important a part of the process as continuity.

You've also got to think about how much Tickell, Rusby, McColl etc. are composers, how much carriers, the role of authority in tradition....

* this could well be true. Or he used a traditional tune.