English: A cast copper alloy key with a circular head (diameter: 27mm). There are four large holes around the outer edge of the head, each having an approximate diameter of 5mm. There is a much smaller hole in the centre of the head with a diameter of 2mm. At four points (in a cross shape) on the head, there are four rivets (diameter: 3mm) that appear to be holding three plates together which make up the head.
There are slight remains of a collar just below the head. The bottom half of the key consists of a hollow oval-sectioned shank (which is partly broken at the end) measuring 61mm in length and the bit, which is made up of two main prongs with a ridge running down the outer edge, is complete.
The overall patina on the key is a rather patchy green/ brown colour. There is slight damage to the head where part of the outer plate has broken away. Additionally, there is a hole of 6mm in length along the shank and just below the collar.
Parallels of keys with a circular head similar to this one are less common than other types of keys, but there is a close example in the Museum of London's Medieval Catalogue, 1965, Plate XXX, No 25 which can be dated to the 12th-14th centuries.