Jansch had been playing Black Water Side live well before the Jack Orion sessions and Al Stewart, who’d been following Jansch's gigs closely, had figured out what he thought was Jansch's take on the track, though he used the wrong tuning. Stewart was in the middle of recording his first album, with Jimmy Page playing the sessions and during a tea break Stewart taught Page his version, which subsequently appeared on Led Zeppelin as Black Mountain Side.
After that, the traditional Pretty Polly rounds out an album that might have been light on for original material (though Jansch’s original material drew heavily on traditional sources anyway) but set the groundwork in place for Pentangle’s exploration of the same themes and set things up (at least that’s the way it looks with the benefit of hindsight) for the traditional goes electric approach taken by Fairport Convention, Ashley Hutchings’ various projects along the same lines and much of what followed through to the present.
Hugely influential and required listening for anyone interested in the field.