It's worth rereading Bronson on the matter. He also prints versions of 'Hares on the Mountain' in an appendix. Again though he makes that same slip of stating he thinks 'Hares' probably derived from 'Twa Magicians'. Why do these earlier scholars assume that if two ballads are on the same theme one always has to derive from the other? In many cases the themes are floating about in all sorts of folklore and on the continent.