It may substitute for the torse (a twisted roll of fabric) in the heraldic achievement of a person of special honour granted the privilege by the monarch.
In the 17th and 18th centuries, a Muscovy hat was sometimes depicted above the coat of arms of the City of London, in place of the more conventional helm and crest of a dragon's wing charged with a red cross.
[5][6] The confusion as to nomenclature stems from references in early borough charters granting the right to the use of a ceremonial sword which is often mentioned in addition to the right to a cap of maintenance.
However, this was intended to mean that in civic processions a cap of maintenance should be carried along with the sword (and mace), signifying that the mayor was the sovereign's representative.
In many English towns where the privilege of a sword was granted by the Crown (for example York, Bristol, Coventry, Lincoln, Newcastle upon Tyne, Norwich, Worcester, Hereford, Exeter, and Hull[7]) the swordbearer wears a variant of the City of London Muscovy Hat, although some wear other sorts of eccentric headgear which they mistakenly also call a "cap of maintenance".
The City of York claims the grant of a cap of maintenance from the Yorkist King Richard III (1483–1485)[8][9] and incorporates this into its coat of arms as a quasi-crest but reverses it so that the tail or peak faces to dexter (viewer's left), thus further compounding the confusion.