The apparent impregnability of Ctesiphon, along with his desire to defeat Shapur the Persian king in battle, resolved Julian to abandon the siege.

The river fleet which had accompanied the march of the army was abandoned to the flames, and Julian, relying on the fertility of the country for provisions for the troops, ordered the baggage train to be burnt, only 20 days' supplies being preserved.

Incapable of forcing a battle, Julian fell back on the Tigris, resolved on a retreat north-westwards to the Roman province of Corduene, before his scanty and rotting provisions should run out.

Although the Persians were rebuffed and Julian's retreat was enabled to proceed, the losses were considerable on his side as well, and the retardation of his march contributed to weakening the army whose provisions were on the verge of giving out.

[3] The subsequent death of Julian in the action of Samarra, which was similarly a tactical success for the Romans, contributed to lower the morale of the troops, and the emperor Jovian, whom they elected in the camp as Julian's successor, was brought by the threat of famine and the Persian army to conclude a disgraceful peace with Shapur II, conceding all the gains of the treaty of Diocletian (298), and important border fortresses such as Nisibis and Singara, as well.