The Amazing Blondel was recorded at the time of the crusades

That's a recording I'd love to hear! Otherwise, it would appear they're still going strong - http://uk.youtube.com/watch?v=LPs0gr5zbII

Seriously, the first true Folk Singer must have been John Jacon Niles - http://uk.youtube.com/watch?v=bpaAeqBhwrM - or some such, given that Folk Music didn't exist until was defined 1954, so before that time they must have been doing somethin' else...