Contorniate

A contorniate, or contourniate, is a species of medal or medallion of bronze, having a deep furrow on the contour or edge, as if the object had been turned in the lathe. Contourniate medallions were struck in the days of Constantine and his successors. These medals were not struck to be a form of money, but are believed to have been given as gifts, and show the portrait of a variety of earlier emperors.