It might have been expected that the Romans would here have made a stand.  The siege of a fortified place by cavalry is ridiculous, if we understand by siege anything more than a very incomplete blockade.  And the Parthians were notoriously inefficient against walls.  There was a chance, moreover, that Artavasdes might have been more successful than his ally, and, having repulsed the Parthian monarch, might march his troops to the relief of the Romans.  But the soldiers were thoroughly dispirited, and would not listen to these suggestions.  Provisions no doubt ran short, since, as there had been no expectation of a disaster, no preparations had been made for standing a siege.  The Greek inhabitants of the place could not be trusted to exhibit fidelity to a falling cause.  Moreover, Armenia was near; and the Parthian system of abstaining from action during the night seemed to render escape tolerably easy.  It was resolved, therefore, instead of clinging to the protection of the walls, to issue forth once more, and to endeavor by a rapid night march to reach the Armenian hills.  The various officers seem to have been allowed to arrange matters for themselves.  Cassius took his way towards the Euphrates, and succeeded in escaping with 500 horse.  Octavius, with a division which is estimated at 5,000 men, reached the outskirts of the the hills at a place called Sinnaca, and found himself in comparative security.  Crassus, misled by his guides, made but poor progress during the night; he had, however, arrived within little more than a mile of Octavius before the enemy, who would not stir till daybreak, overtook him.  Pressed upon by their advancing squandrons, he, with his small band of 2,000 legionaries and a few horsemen, occupied a low hillock connected by a ridge of rising ground with the position of Sinnaca.  Here the Parthian host beset him; and he would infallibly have been slain or captured at once, had not Octavius, deserting his place of safety, descended to the aid of his commander.  The united 7,000 held their own against the enemy, having the advantage of the ground, and having perhaps by the experience of some days learnt the weak points of Parthian warfare.

Surenas was anxious, above all things, to secure the person of the Roman commander.  In the East an excessive importance is attached to this proof of success; and there were reasons which made Crassus particularly obnoxious to his antagonists.  He was believed to have originated, and not merely conducted, the war, incited thereto by simple greed of gold.  He had refused with the utmost haughtiness all discussion of terms, and had insulted the majesty of the Parthians by the declaration that he would treat nowhere but at their capital.  If he escaped, he would be bound at some future time to repeat his attempt; if he were made prisoner, his fate would be a terrible warning to others.  But now, as evening approached, it seemed to the Parthian that the prize which he so much desired was about to elude his grasp.