History of Wars Summary 19 - Roman-Persian Wars 5: Julian's Persian Expedition

In the 4th century, the rivalry between Rome, which had adopted Christianity, and the Sasanian Empire, centered around Zoroastrianism, began to intertwine with religious issues. As Christianity's status significantly rose within the Roman Empire after the reign of Constantine the Great, the Sasanian Empire grew suspicious of its own Christians as potential pro-Roman elements. Concurrently, conflicts over the control of Armenia and Mesopotamia persisted. Shapur II engaged in prolonged warfare with Rome, and Emperor Julian launched a large-scale expedition in 363. The Roman army advanced near Ctesiphon but could not push further due to supply issues and Sasanian resistance. After Julian was killed in battle, his successor Jovian retreated the army and signed a peace treaty with the Sasanian Empire. This treaty led Rome to cede some eastern territories, and the borders were readjusted. The wars of the 4th century confirmed that neither nation could easily conquer the other.