In his third campaign Philippicus adopted a bolder line of proceeding.  Commencing by an invasion of Eastern Mesopotamia, he met and defeated the Persians in a great battle near Solachon, having first roused the enthusiasm of his troops by carrying along their ranks a miraculous picture of our Lord, which no human hand had painted.  Hanging on the rear of the fugitives, he pursued them to Daras, which declined to receive within its walls an army that had so disgraced itself.  The Persian commander withdrew his troops further inland; and Philippicus, believing that he had now no enemy to fear, proceeded to invade Arzanene, to besiege the stronghold of Chlomaron, and at the same time to throw forward troops into the more eastern parts of the country.  He expected them to be unopposed; but the Persian general, having rallied his force and augmented it by fresh recruits, had returned towards the frontier, and, hearing of the danger of Arzanene, had flown to its defence.  Philippicus was taken by surprise, compelled to raise the siege of Chlomaron, and to fall back in disorder.  The Persians pressed on his retreat, crossed the Nymphius after him, and did not desist from the pursuit until the imperial general threw himself with his shattered army into the strong fortress of Amida.  Disgusted and discredited by his ill-success, Philippicus gave over the active prosecution of the war to Heraclius, and, remaining at head-quarters, contented himself with a general supervision.

Heraclius, on receiving his appointment, is said to have at once assumed the offensive, and to have led an army, consisting chiefly or entirely of infantry, into Persian territory, which devastated the country on both sides of the Tigris, and rejoined Philippicus, without having suffered any disaster, before the winter.  Philippicus was encouraged by the success of his lieutenant to continue him in command for another year; but, through prudence or jealousy, he was induced to intrust a portion only of the troops to his care, while he assigned to others the supreme authority over no less than one third of the Roman army.  The result was, as might have been expected, inglorious for Rome.  During A.D. 587 the two divisions acted separately in different quarters; and, at the end of the year, neither could boast of any greater success than the reduction, in each case, of a single fortress.  Philippicus, however, seems to have been satisfied; and at the approach of winter he withdrew from the East altogether, leaving Heraclius as his representative, and returned to Constantinople.

During the earlier portion of the year A.D. 588 the mutinous temper of the Roman army rendered it impossible that any military operations should be undertaken.  Encouraged by the disorganization of their enemies, the Persians crossed the frontier, and threatened Constantina, which was however saved by Germanus.  Later in the year, the mutinous spirit having been quelled, a counter-expedition was made by the Romans into Arzanene.  Here the Persian general, Maruzas, met them, and drove them from the province; but, following up his success too ardently, he received a complete defeat near Martyropolis, and lost his life in the battle.  His head was cut off by the civilized conquerors, and sent as a trophy to Maurice.