§ 43. Medieval sacristies attached to chancels, and especially to aisleless chancels, are common, and are in most cases on the north side, with a door in the north wall close to the altar. Good examples of an ordinary kind are at Islip and Aldwinkle St Peter in Northants. There is a fourteenth century sacristy at Willingham, near Cambridge, with a vaulted ceiling. The vaulted vestry at Burford is of the fifteenth century. Sometimes the sacristy contained an altar, as at Claypole and Westborough, between Newark and Grantham; and it is probable that the sacristies of several of the beautiful chancels already alluded to, as at Hawton, had their altars, which might be used occasionally for mass, but would in any case be useful for laying out and folding up vestments before and after service. The sacristy at Heckington is of two stories, the lower probably intended to be a bone-hole. At Halsall there is a handsome doorway, west of the founder's tomb, through which a chantry chapel is entered: this may have been a sacristy in the first instance. Large sacristies of two, and even three stories are found. The upper room or solar, as at Raunds in Northants, Wath, near Ripon, and other places, was sometimes provided with a window opening into the chancel, and may have served, like the solar of the south porch at Grantham, as the treasury of the church and a room for the deacon or church watcher. But that these upper rooms may have been provided as extra chantry chapels is also probable. The very interesting vestry building between Peterhouse and its appropriated church of Little St Mary's at Cambridge seems to have contained the chantry chapel of John Warkworth, master of Peterhouse, on its upper floor: there is also a piscina in the small lower sacristy, which stands above a bone-hole. The originally very similar building between St Benet's church and Corpus appears to have had chantry chapels on both floors. Perhaps the best example of a two-storied sacristy is the semi-octagonal building, vaulted on both floors, at the east end of the north chancel aisle at Long Sutton, Lincolnshire. This is an exceptional situation; but there was no fixed place for the sacristy. Often, as at Darlington or as the vaulted vestry at Rushton, Northants, it is on the south side of the chancel. In certain places, as at St Peter Mancroft in Norwich, and Lavenham in Suffolk, it projects from the east wall of the church, below the east window, and is entered by a doorway at one or both sides of the altar. Sometimes, again, as at Sawley and Tideswell in Derbyshire, the altar was brought forward from the east wall, and provided with a stone screen wall or reredos, the space between which and the east wall became the sacristy. A similar screening off of the east end of an aisle is found, for example, at Rushden and Higham Ferrers in Northants: in these cases, it has been effected without interfering, as at Tansor, with the proper spacing of the aisle.