History of Wars Summary 19 - Roman-Persian Wars 4: Valerian's Captivity

As the Sasanian pressure intensified, Rome faced a severe crisis in the mid-3rd century. Shapur I exploited Rome's chaos to attack Mesopotamia, and in 260, Emperor Valerian was defeated at the Battle of Edessa and captured. This was a deeply shocking event in Roman history. However, Rome soon counterattacked. Odaenathus, the leader of Palmyra, attacked the Sasanian forces, contributing to the recovery of Roman territories in the East. Emperor Aurelian later reunified the empire. By the end of the 3rd century, Diocletian strengthened the eastern defenses and reorganized the border fortresses and administrative system. In 298, Galerius defeated the Sasanian army, securing favorable terms for Rome. The Treaty of Nisibis strengthened Roman influence in Armenia and ceded parts of Mesopotamia to Rome. However, this peace did not last long.