English: A medieval copper alloy rotary key. The bow is broadly shaped like a quatrefoil, or ‘four-leaf clover’. There are grooves down the shaft from the bow. The shank is ovoid rather than circular in section and flares to form a distinct collar where it joins the bow. This collar has some transverse linear grooving. The shank is hollow. The bit has three clefts between the four wards, all of which are transverse to the shank. One face of the bit has two channels and the other has one channel, all of which are offset from one another. It measures 88.3mm x 30.3mm x 9.8mm, weighing 41.05g. In he Museum of London's “Medieval Catalogue" (1940 p133-144), Ward Perkins has introduced a classification system for door and chest keys. The key described in this record is most closely related to his Type VI. Ward Perkins describes the type: “They are characterized by the solid shank, bored at the end to leave a conical hole, by the massive bit, and by the elaborate form of the bow. The latter may be lobed or lozenge-shaped or a combination of both, and occasionally the corners of the lozenge are elaborated…” (p140). Ward Perkins dates a number of closely related copper alloy keys of Type VI to the 14th and 15th centuries, and this may be an appropriate date range for this key. Parallels can also be seen in Ottaway and Rogers (2002) Finds from Medieval York. York Archaeological Trust: York.