A single coin discovered in a field at Chalgrove, Oxfordshire, UK, has proved to have an exceptional significance in the world of Roman numismatics. It features a third-century emperor, Domitianus, unknown apart from a find of 1900 from a vineyard in Cléons previously described as ‘doubtful’. The dies used to strike the two coins match, leaving little doubt that Domitianus was a real person, although of somewhat fleeting dominion over the Gallic Empire – for a brief period in AD 271.