Yeoman's Service

A servant in a royal or nobleman's household, ranking between a sergeant and a groom. Used to designate their more specific duties with such titles as:

yeoman of the bottles,
yeoman of the buttery,
yeoman of the cellar,
yeoman of the chamber,
yeoman of the crown,
yeoman of the ewery,
yeoman of the horse,
yeoman for the household,
yeoman of the larder,
yeoman for the mouth,
yeoman of the revels,
yeoman of the robes,
yeoman of the sauces,
yeoman of the stable,
yeoman of the stirrup,
yeoman of the tents, and
yeoman of the wardrobe (OED).

"I once did hold it a baseness to write fair;
but Sir now, it did me Yeoman's service."

Shakespeare, Hamlet (1602)