Having gained over, as he thought, Alamundarus, the leader of the Saracens dependent on Persia, and collected a fleet to carry his stores, he marched from Gircesium down the course of the Euphrates, intending to carry the war into Southern Mesopotamia, and perhaps hoping to capture Ctesiphon.

He expected to take the Persians unawares, and may not unnaturally have looked to gain an important success; but, unhappily for his plans, Alamundarus proved treacherous.
The Persian king was informed of his enemy's march, and steps were at once taken to render it abortive.

Adarman was sent, at the head of a large army, into Roman Mesopotamia, where he threatened the important city of Callinicus in Maurice's rear.

That general dared advance no further.

On the contrary, he felt constrained to fall back, to give up his scheme, burn his fleet, and return hastily within the Roman frontier.