The 'unknown to whom?' point is vital - I was somewhat traumatised one Sunday morning when, on his Radio 2 programme, Michael Parkinson's response to a reference to Martin Carthy by one of his guests was 'Never heard of him' and seem rather bemused by the guest's enthusiasm for this 'unknown' folk singer.

On the other hand, I do know about Lennie Gallant and his 'Nelly J. Banks' is in my repertoire.