I think Donavan did it mostly parallel to Judy Collins in the late 60s/early 7os, Angelo Branduardi did it as well in the 8os and I also recorded it with OAKTREE in...-puh- ... I can't recall exactly but it was 'round '86-'87 on our first recording "Come To The Land Of The Oaktree".
A great song I'm still singing today. At the moment we're(Celtic Harvest) working on a folk-rock-version of it.