Leadbelly was the source for Black Betty, whether or not he wrote it isn't clear. A lot of singers have sung and recorded it over the years, many blues revivalists during the sixties. Tom Jones was the first (I think) to do it as a pop song, but no one changed it much from the original version.

Leadbelly's Black Betty

Tom Jones' Black Betty

Sheryl Crowe's Black Betty

Ram Jam's Black Betty