Rise to power
Jovian was born at Singidunum in 330, the son of the commander of Constantius II's imperial bodyguards. He also joined the guards, and by 363 had risen to the post that his father had once held. He accompanied the Roman Emperor Julian on the disastrous Mesopotamian campaign of the same year against Shapur II, the Sassanid king. After a small but decisive engagement the Roman army was forced to retreat from the numerically superior Persian force. Julian had been mortally wounded during the retreat and Jovian seized his chance. Some accounts have it that on Julian's death Jovian's soldiers called out "Jovianus!" The cry was mistaken for "Julianus", and the army cheered Jovian, briefly under the illusion that the slain Emperor had recovered from his wound.
Shapur pressed his advantage and Jovian, deep inside Sassanid territory, was forced to sue for peace on very unfavourable terms. In exchange for safety he agreed to withdraw from the provinces east of the Tigris that Diocletian had annexed and allow the Persians to occupy the fortresses of Nisbis, Castra Maurorum and Singara. the King of Armenia, Arshak II, was to stay neutral in future conflicts between the two empires, and was forced to cede some of his kingdom to Shapur. The treaty was seen as a disgrace and Jovian rapidly lost popularity.
After arriving at Antioch Jovian decided to hurry to Constantinople to consolidate his position.
- Banchich, Thomas, "Jovian", De Imperatoribus Romanis.