I don’t know if I ever missed this thread, or dismissed it, it’s been so long. But now that new member dedindi (Welcome, BTW) has (re-)brought it to my attention, I’ll put my 2 farthings in:
Only the first five notes of Carolan’s Dream have anything even remotely in common with Stairway to Heaven. Borrowing? Sure, maybe, could be … I guess. Influence? For an entire, otherwise completely unrelated song? Now we’re straying into the woods. The progression is too miniscule, and not really unique at all, so thus far all we have is idle conjecture over what might be sheer coincidence. Has anyone from Led Zep said anything about it? Are they even aware that this is an internet topic? I’d like to hear it from the horse’s mouth. That should clear things up. If it’s true, I’d commend them for their taste in sources, but the suggestion that borrowing an unremarkable five-note progression is plagiarism…? Literally, I’m laughing out loud as I type this.
O’Carolan would probably be secretly flattered.