An Etymological Dictionary of the German Language/Marschall
Marschall, m., ‘marshal,’ derived, partly under the influence of Fr. maréchal, from MidHG. marschale, m., which lit. and orig. signified ‘horse-servant,’ then ‘overseer of the train of servants on journeys and expeditions, as a municipal or court official; marshal.’ OHG. marahscalc is a compound of Schalk, ‘servant,’ and marah, ‘horse’; even the Lex Salica and the Leg. Alem. record the term mariscalus, besides which, in MidLat. marscallus occurs. From Teut. are derived the Rom. cognates — Ital. mariscalco, Fr. maréchal, ‘farrier, marshal,’ as well as the MidLat. version, comes stabuli, Fr. connétable. OHG. marah, n., MidHG. marc, n., ‘steed, horse,’ AS. mearh, Scand. marr, n..; Goth. *marh is wanting. It originated, in exact accordance with the permutation of consonants, from pre-Teut. marka-, in which form it is recorded as OKelt. by Pausanias; comp. with this OIr. marc and W. march, ‘horse.’ There is, however, no linguistic necessity for deriving Teut. marha- from Kelt. The word marh, the fem. of which, Mähre, has been preserved, was supplanted at a later period by Roß and then Pferd. To this word Marstall is akin.