Second Mesopotamian campaign of Ardashir I

In 237–241 during the reign of Maximinus the Thracian, who succeeded Severus Alexander, the last emperor of the Severan dynasty, the cities of the Roman province of Mesopotamia, Nisibis and Carrhae, were conquered by the Sasanian Empire. Herodian suggested that the Sasanians had remained quiet for three or four years after Severus Alexander's campaigns of 232–233, the outcome of which was inconclusive. ==238/239==

A new large-scale invasion by the Sasanian armies occurred later that year, which laid siege to the fortress-city of Dura Europos, a Roman outpost on the Euphrates River, but it was repulsed by the Romans. ==240/241==

In the course of that year, it appears that Ardashir I finally succeeded in the feat of occupying and destroying the important Roman-allied city-stronghold of Hatra,), perhaps even going so far as to besiege and occupy Antioch itself, as seems to be suggested by the fact that its mint stopped minting coinage for the years 240 and 241. ==References==