Battle of Singara (344)

When Shapur II, who ascended to the throne of the Sasanian Empire in 309 (at the time an unborn infant), came of age and took in hand the administration of his kingdom, he dedicated himself to a lifelong mission of restoring his country's military power, and avenging its recent defeats sustained against the Romans and Saracens. After thoroughly subduing the Lakhmid Arabs rebellion in the south, he directed his attention towards Rome, his main enemy, in 337.[6][7] The sacking of a Sasanian city and the deportation of its population may have led to the intervention of Shapur II.[8] He began by recapturing Armenia. and then advanced in his first campaign against Constantius II in the following year, however, the Roman defensive lines resisted and the Persian forces made limited progress.[9]

In 344, Shapur raised an army that included foot archers, mounted archers, regular cavalry, cataphracts, slingers, and hoplites.[10] The preparation of such a massive army was not unnoticed by the Roman Emperor since his spies informed him of every move the Sasanians made.[11]

The Romans retired their frontier troops and the Persian forces subsequently crossed the Tigris river.[12] Shapur's tactic was to tire the Roman forces with a long march in the hot hours of the day before engaging them with his archers and cataphracts,[13] thus, when the two armies came face-to-face, the Persian cavalry feigned flight and the overconfident Romans then pursued them for more than 18 kilometers, reaching Singara while the Sasanians had cut off their communication lines.[14]

When the Persian cavalry reached an elevated position during their retreat, they halted and shot arrows down onto the Roman forces who were probably using the tortoise order to resist the enemy's arrows.[15] The Roman army included in its ranks elite units, the club-bearers/mace-bearers who were trained to fight against the Sasanian clibanarii.[16] Close to the night evening, the Roman forces reached the Persian camp and, while Constantius asked them to halt in vain, engaged the Persian troops. The Roman club bearers' tactic was effective and simple, each of them had to charge the clibanarii opposite him, to sidestep or deflect his enemy's kontos and hit the rider with his mace in order to knock him off his horse.[17] When Shapur realised that the Romans had brought a huge army that outnumbered his own forces, he decided to leave for the Tigris and left his son in charge of the Sasanian army.[18] The Roman troops smashed down the defences of the Persian camp,[19] inflicted heavy casualties,[20] captured Shapur's son, and tortured him to death.[21] However, the Roman forces inside the Persian camp made a mistake when they used torches to light their way and while the exhausted Roman soldiers were recovering, the Sasanian troops, helped by the light of the torches, suddenly fired a deadly barrage of missiles with high accuracy and launched a general counter-attack that inflicted massive casualties on the Roman troops who were unable to resist.[22][23]

The death of Shapur's son did not facilitate an amicable settlement of the conflict, and the war dragged on for several years. Shapur, notwithstanding the extent of his victory, proved unable to utilize the event to any further advantage. Two years later, he became bogged down in another siege of Nisibis, but was once more repelled with losses;[24] he was then obliged to break off the war to meet the threat of nomadic barbarian invasions in Sogdiana in the far east.[25] The war resumed in 359 CE, but ended with no conclusive result. In 363 it was taken up energetically by Julian, who died and suffered a decisive defeat. His successor, Jovian, was forced to cede extensive Roman territory in the treaty of Dura, and thus Shapur's ambitions were accomplished.

• Perso-Roman wars of 337–361
• Siege of Amida