Much the Miller's son occurs as one of the 3 principal associates of Robin Hood in the Little Geste. There don't seem to have been many candidates for Much in previous RH theories. Believe it or not but we found a seeming candidate in Roger Godberd records.
We suggest that Much the Miller's son of RH traditions & stories may match "William Mungumry, father, William Maysam" in the Godberd records. The names Much and Mungumry are similar. Much the Miller's son could be either "Much the-Miller's-son" or "Much-the-Miller's son", and the latter could match the "father" of the records. "Miller's son" is also possibly similar to Maysam? William & Miller are also similar?
Much is otherwise also said to be cognate with the Mitch & Mickey nicknames for Michael. Godberd records mention "feast of St Michael" 1270, and "quindene (after the day) of St Michael" 1272. It might be possible that these were conflated in since there are also some other similar seeming conflations with other persons etc.
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Other earlier and later candidates for Much the Miller's son have included: The Miller of Mansfield; Johanne Molendinario de Lyndeby (1287); John de Midgley late 1200s; Robert le Mouner of Paynel Hoton (Skelbrooke, 1294); Geoffrey le Mouner/Miller of Skelbrook (1293); Michael son of Stephen Moledenarius/Miller of Eastwood; Adam Hood; Johannes/Johannus Hood the Miller; the Miller in Chaucer's Canterbury Tales.