Copper-alloy, 5.00 grams, 18.01 mm. 1st-4th century AD. A delicate cast finger ring made with a transverse plate - the key - mounted on an upright bar. The leading edge of the plate is cut to form prongs which correspond to the tumblers within a tumbler lock; the maker has used intersecting triangles resembling a capital 'M'. Key finger rings of this type were used to secure portable caskets and boxes. Reference: Hattatt, R. Ancient Brooches and Other Artefacts, Oxford, 1989, p.457-9 and Read, B. Metal Artefacts of Antiquity, Langport, 2001, p.61. Good fine condition. Provenance: from an old English collection.