SIRM. - Letters engraved at the bottom of certain coins, doubtless designating Sirmium Pannoniae, at present Sirmich in Sclavonia [Sremska Mitrovica, Serbia]. -This mint mark is seen on the exergue of medals, struck under the Constantius Chlorus, Licinius jun., Constantine the Great, Crispus, Fausta, Constantine jun., Julian II., Jovian, Valentinian I., and other Augusti and Caesars of the Late Empire