 Working closely with the Treasurer, the Cofferer usually served as "locum tenens" when the Treasurer was otherwise engaged with affairs of state (as was often the case); thus the Cofferer came to be seen as, in effect, the working head of the Wardrobe, acting on the Treasurer's behalf.In his own right he oversaw a small accounting office, staffed by the 'clerks of the Cofferer', who went on to play a key role in the financial oversight of the Household; this was a precursor to the Board of Green Cloth).As early as the 1220s certain persons are identified as having a specialised role as 'buyer' or 'purveyor' within the King's Wardrobe, and keeping their own accounts.