Copper-alloy, 9.02 grams, 23.73 mm. Circa 2nd century AD. A finely modelled Celtic style cast face mount, with large eyes, hair and wearing a 'liberty cap' helmet. With part of a thin back plate; being part of military belt plate or similar and a rectangular fixing stud to the reverse. Reference: Andrew Appels & Stuart Laycock Roman Buckles & Military Fittings, page 191, for similar example. An excellent and attractive piece.