Nisibis, at this time a Roman colony, was strongly situated on the outskirts of the mountain range which traverses Northern Mesopotamia between the 37th and 38th parallels.

The place was well fortified and well defended; it offered a prolonged resistance; but at last the Avails were breached, and it was forced to yield itself.

The advance was then made along the southern flank of the mountains, by Carrhae (Harran) and Edessa to the Euphrates, which was probably reached in the neighborhood of Birehjik, The hordes then poured into Syria, and, spreading themselves over that fertile region, surprised and took the metropolis of the Roman East, the rich and luxurious city of Antioch.

But meantime the Romans had shown a spirit which had not been expected from them.

Gordian, young as he was, had quitted Rome and marched through Mossia and Thrace into Asia, accompanied by a formidable army, and by at least one good general.
Timesitheus, whose daughter Gordian had recently married, though his life had hitherto been that of a civilian, exhibited, on his elevation to the dignity of Praetorian prefect, considerable military ability.
The army, nominally commanded by Gordian, really acted under his orders.
With it Timesitheus attacked and beat the bands of Sapor in a number of engagements, recovered Antioch, crossed the Euphrates, retook Carrhae, defeated the Persian monarch in a pitched battle near Resaina (Ras-el-Ain), recovered Nisibis, and once more planted the Roman standards on the banks of the Tigris.