E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
means an ostler or groom. His original duty was to feed, groom, shoe, and physic his masters horse. (British, marc, a mare; scalc, a servant.)
Marshal Forward. Blucher; so called for his dash and readiness in the campaign of 1813.
Marshal of the Army of God, and of Holy Church. The Baron Robert Fitzwalter, appointed by his brother barons to lead their forces in 1215 to obtain from King John redress of grievances. Magna Charta was the result.