Jeesh, I was raised on Zep and even I didn't know some of this, or the other stuff, y'all musical savants or somethin'!
I honestly never knew a Zeppelin fan that didn't know that Zeppelin originated out of the Yardbirds. In fact, Zeppelin was just a vehicle for Page to fill Yardbirds contractual obligations as everyone else quit to go form Renaissance, who itself would completely turn over their membership and go on to have some success in the 70's as an Annie Haslam/Michael Dunford led band.
As for Fairport, I do have that CD. I tried getting into them, I just never could for some reason. I love the Strawbs not really for their pure folk beginnings, but for what they did in the 70's, after Rick Wakeman showed them the way.
Even though Wakeman bailed on the Strawbs to go off and join some nobodys named Yes, he kept in touch with his former band mates. The song is early 70's but the performance is obviously 80's
The Hangman and the Papist