Khosrau intervenes in Lazica and supports the weakened king Gubazes II against a full-scale uprising.

He sends an expeditionary force under Miohr-Mihroe (Mermeroes in Byzantine sources) and captures the Roman stronghold of Petra, located on the coast of the Black Sea, which provides the Persians a strategic port.

King Gubazes II revolts against the Persians and requests for aid from Justinian I.

He sends an expeditionary force of eight thousand men under Dagisthaeus, who together with a Lazic force lays siege to the Persian garrison at Petra.

As the Persians are well provisioned, the siege drags on.

Dagisthaeus has neglected to keep watch over the mountain passes that led into Lazica, and a far larger Persian relief force under Mihr-Mihroe arrives and raises the siege, yet the Persians lack sufficient supplies.

Mihr-Mihroe departs after strengthening the garrison at Petra and leaving a further five thousand men under Phabrizus to secure its supply routes.

Gubazes and Dagisthaeus combine their forces in the spring of 549 to destroy Phabrizus's army in a surprise attack; they pursue the survivors into Caucasian Iberia.

In the same summer, they win another victory against a new Persian army, led by Khorianes.

The allies fail, however, to prevent another Persian army from reinforcing Petra, and Dagisthaeus is recalled and replaced by Bessas.

The new imperial commander Bessas quells a pro-Persian revolt of the Abasgi tribe, takes Petra and defeats Mermeroes at Archaeopolis in 551.

However, …

…the latter manages to capture the town Kutaisi and the Uchimerion fortress blocking the important roads to the mountains.

The Sabir live predominantly in the region of Azerbaijan and Dagestan bounded on the east by the Caspian Sea, on the west by the Caucasus Mountains.

Priscus mentions that the Sabir attacked the Saragur, Urog and Unogur tribes in 461, forcing them North to the Volga once more, as a result of having themselves been attacked by the "Avars".

In 515, having recovered from the Avar attacks of the 460s, they "advertised their power in a huge raid south of the Caucasus, in which they attacked Iranian and Byzantine lands with scrupulous impartiality".

However, in the face of the increasing Avar threat, the Sabirs, previously allied with Sassanid Persia, switch their allegiance to Constantinople in 551 and invade the Caucasus.

The imperial army and their Sabir allies (some six thousand men) under Bessas recapture the strategic imperial fortress of Petra, located on the coast of the Black Sea.

Bessas orders the city walls razed to the ground, but a new army under Mihr-Mihroe is able to establish Persian control over the eastern part of Lazica.

The imperial forces in Lazica withdraw west to the mouth of the Phasis, while the Lazi, including Gubazes and his family, seek refuge in the mountains.

Gubazes, despite enduring harsh conditions in the winter of 551/552, rejects the peace offers conveyed by envoys from Mihr-Mihroe.

The Persians receive substantial reinforcements in 552, but their attacks on the fortresses held by Constantinople and the Lazi are repulsed.

Mihr-Mihroe had, through a ruse, succeeded in dislodging the imperial forces in 554 from Telephis, their most forward position, causing a general retreat along the Phasis river.

He had not pursued them, however, or otherwise pressed his advantage, due to his own army's lack of supplies.

After strengthening his own forts, he had returned to Mocheresis.

There he fell ill, and withdrew to Iberia; he dies of his illness at Mtskheta in the summer of 555.