E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Groom of the Stole.
Keeper of the stole or state-robe. His duty, originally, was to invest the king in his state-robe, but he had also to hand him his shirt when he dressed. The office, when a queen reigns, is termed Mistress of the Robes, but Queen Anne had her Groom of the Stole. (Greek, stol, a garment.) (See BRIDEGROOM.)