By: Mir M.Hosseini
Constantine 2 started another war with Shapour 2 after a year of peace. The Roman Empire was split into two regions and Christianity was spread throughout the Eastern Roman Empire, hence the nature of wars changed as Iranians promoted the Zoroastrian religion. During the first decade the conflicts did not result in a decisive victory, but by 358 the war turned sharply in Iran's favor. Shapour 2 conquered much territory, and the Julian was killed on a campaign against Tisfun. His successor then concluded a disgraceful peace, that marked the end of 13 years of war. Romans gave up whatever they had seized east of the Mediterranean
Sea. Historians mostly refer to these wars as the first round of Persian-Roman wars.
The second round started in 359 ending with Persian's victory.