Roman soldiers garrisoned at Dura-Europos, a fortified frontier town on the middle Euphrates facing the Parthian and later Sasanian Persian empires across the river, built their mithraeum the way mithraea were built everywhere in the Roman world, as a small, deliberately cave-like room with benches along both long walls where a limited membership could recline for a shared ritual meal beneath a central image of Mithras slaying the bull. What sets the Dura example apart is not its architecture but its inscriptions: dedicatory texts naming specific individual soldiers survive here in a density unmatched at most other mithraea, giving historians a rare, precisely dated record of exactly which military personnel were initiated into the cult at a single garrison and roughly when.
The mithraeum's dedication, not a later enlargement, dates to around 168 CE, attested by a Palmyrene inscription naming the officer commanding the garrison's archers who commissioned it. The building was subsequently enlarged and renovated in 209-211 CE, and enlarged again around 240 CE in a final building phase, and it is this later, expanded structure whose wall paintings survive, including a scene showing Mithras hunting on horseback, a variant image far less common than the standard bull-slaying tauroctony found in almost every other mithraeum and one that spoke directly to the Palmyrene archers who worshipped there, suggesting local variation within what is otherwise one of the more visually standardized cults of the Roman world.