He might send a subsidiary force by the doubtful route which could advance to his aid if matters went favorably, or remain on the defensive if they assumed a threatening aspect; but his own grand attack must be by the other.

Accordingly he divided his forces.
Committing a body of troops, which is variously estimated at from 18,000 to 30,000, into the hands of Procopius, a connection of his own, and Sebastian, Duke of Egypt, with orders that they should proceed by way of the Mons Masius to Armenia, and, uniting themselves with the forces of Arsaces, invade Northern Media, ravage it, and then join him before Ctesiphon by the line of the Tigris, he reserved for himself and for his main army the shorter and more open route down the valley of the Euphrates.

Leaving Carrhae on the 26th of March, after about a week's stay, he marched southward, at the head of 65,000 men, by Davana and along the course of the Belik, to Callinicus or Nicophorium, near the junction of the Belik with the Euphrates.

Here the Saracen chiefs came and made their submission, and were graciously received by the emperor, to whom they presented a crown of gold.

At the same time the fleet made its appearance, numbering at least 1100 vessels, of which fifty were ships of war, fifty prepared to serve as pontoons, and the remaining thousand, transports laden with provisions, weapons, and military engines.
From Callinicus the emperor marched along the course of the Euphrates to Circusium, or Circesium, at the junction of the Khabour with the Euphrates, arriving at this place early in April.