The advantage gained at Constantina is lost later in the year when his successor as magister militum of the East, John Mystacon, is defeated on the river Nymphios by Sassanid general Kardarigan.

Kardarigan had first appeared as commander of the Persian forces in northern Mesopotamia in late 582, when he opposed a Byzantine invasion of Arzanene under John Mystacon and defeated him at a battle at the river Nymphius.

In the campaign of 583, he laid siege to the fort of Aphumon, but had abandoned the siege to help repel an imperial attack on the newly constructed fort of Akbas.

While he was preparing an incursion into Byzantine territory in autumn 584, he had been forced to turn east to counter an imperial invasion under Philippicus.

In 585, while Philippicus falls ill, Kardarigan goes on the offensive, besieging the imperial base of Monocarton.

The siege fails, and he then marches north to …

…Martyropolis, Philippicus's base; after sacking a monastery near the city, however, he returns to Persian territory.

Kardarigan attacks the army of Philippicus at Solachon in summer 586, commanding the central division of the Persian army in person.

The battle ends in a heavy defeat, and although Kardarigan himself escapes, the survivors of his army suffer greatly because of his decision to destroy his army's water supplies before the battle, in an attempt to harden his men's resolve.

In addition, the surviving Persians are refused entry into Dara since, according to Simocatta, Persian custom forbade entrance to fugitives.

Simocatta also narrates that many Persians died of thirst or from water poisoning when they drank too much water from wells after their ordeal.

Nevertheless, while Philippicus proceeds to attack the fortress of Chlomaron, Kardarigan manages to assemble an improvised force, mostly composed of peasant levies.

He then marches to Chlomaron and unites his army with its defenders, forcing the imperial general to raise the siege.

Kardarigan thus escapes, although his men suffer further casualties in the process, up to a thousand according to Simocatta, from imperial patrols.