Large Roman Intaglio of Caracalla?.
This is a very large intaglio of Roman date set into a plate brooch very probably reset later in roman antiquity. Proffessor Martin Hennig of Oxford University has told me it could well be of Caracalla in the guise of Hercules. The main thinking of the character being an emperor is the radiate style crown on the head. Martin thinks the gem is of third century date. Septimus severus and his sons did campaign in scotland in 209-210ad and were resident in York where royal ingravers could have also been based at that time. If anyone has any thinking on this I would be greatful. Does it resemble any coin die? or does hercules have the rays coming from his head on any other coin?.