His great army, collected from all quarters, was intact; he had not yet condescended to take the field in person; he had lost no important town, and his adversary had tacitly confessed his inability to form the siege of a city which was far from being the greatest in the empire.

If Sapor, therefore, really made at this time overtures of peace, it must have been either with the intention of amusing Julian, and increasing his difficulties by delaying his retreat, or because he thought that Julian's consciousness of his difficulties would induce him to offer terms which he might accept.
The retreat commenced on June 16.

Scarcely were the troops set in motion, when an ominous cloud of dust appeared on the southern horizon, which grew larger as the day advanced; and, though some suggested that the appearance was produced by a herd of wild asses, and others ventured the conjecture that it was caused by the approach of a body of Julian's Saracenic allies, the emperor himself was not deceived, but, understanding that the Persians had set out in pursuit, he called in his stragglers, massed his troops, and pitched his camp in a strong position.

Day-dawn showed that he had judged aright, for the earliest rays of the sun were reflected from the polished breastplates and cuirasses of the Persians, who had drawn up at no great distance during the night.

A combat followed in which the Persian and Saracenic horse attacked the Romans vigorously, and especially threatened the baggage, but were repulsed by the firmness and valor of the Roman foot.