Siege of Dura-Europos
250 CE.
Shown on the map at 34.748°, 40.730°.
The siege of Dura Europos took place when the Sasanians under Shapur I besieged the Roman city of Dura-Europos in 256 after capturing Antioch. Dura-Europos was an important trading center in Roman Syria. It may or may not be the same as the "Doura" recorded in Shapur I's inscriptions. The town was in Sasanian hands for some time after its fall, and was later abandoned. Intact archaeological evidences at Dura provide details of the Roman presence there, and the dramatic course of the siege. The garrison was determined to resist the siege, and the Sasanians employed a variety of siege warfare techniques to defeat them. Archaeological evidences suggest that the garrison at Dura-Europos was mixed, composed of Cohors XX Palmyrenorum (which is known more than the others), vexillations from Legio IV Scythica Valeriana Galliena, III Cyrenaica, XVI Flavia Firma, and other cohorts, including Cohors II Paphlagonum Galliana Volusiana and possibly Cohors II Equestris. The relationship between these forces are uncertain. XX Palmyrenorum was certainly based in Dura-Europos, and may have been an "inferior" contingent of the garrison relative to the legionaries.
Text from the Wikipedia article Siege of Dura-Europos (256), licensed CC BY-SA 4.0.