Relieved from this peril, Kobad would at once have declared war against Justin, and have marched an army into Roman territory, had not troubles broken out in Iberia, which made it necessary for him to stand on the defensive. Adopting the intolerant policy so frequently pursued, and generally with such ill results, by the Persian kings, Kobad had commanded Gurgenes, the Iberian monarch, to renounce Christianity and profess the Zoroastrian religion. Especially he had required that the Iberian custom of burying the dead should be relinquished, and that the Persian practice of exposing corpses to be devoured by dogs and birds of prey should supersede the Christian rite of sepulture. Gurgenes was too deeply attached to his faith to entertain these propositions for a moment. He at once shook off the Persian yoke, and, declaring himself a vassal of Rome, obtained a promise from Justin that he would never desert the Iberian cause. Rome, however, was not prepared to send her own armies into this distant and inhospitable region; her hope was to obtain aid from the Tatars of the Crimea, and to play off these barbarians against the forces wherewith Kobad might be expected shortly to vindicate his authority. An attempt to engage the Crimeans generally in this service was made, but it was not successful. A small force was enrolled and sent to the assistance of Gurgenes. But now the Persians took the field in strength. A large army was sent into Iberia by Kobad, under a general named Boes. Gurgenes saw resistance to be impossible. He therefore fled the country, and threw himself into Lazica, where the difficult nature of the ground, the favor of the natives, and the assistance of the Romans enabled him to maintain himself. Iberia, however, was lost, and passed once more under the Persians, who even penetrated into Lazic territory and occupied some forts which commanded the passes between Lazica and Iberia.
Rome, on her part, endeavored to retaliate (A.D. 526) by invading Persarmenia and Mesopotamia. The campaign is remarkable as that in which the greatest general of the age, the renowned and unfortunate Belisarius, first held a command and thus commenced the work of learning by experience the duties of a military leader. Hitherto a mere guardsman, and still quite a youth, trammelled moreover by association with a colleague, he did not on this occasion reap any laurels. A Persian force under two generals, Narses and Aratius, defended Persarmenia, and, engaging the Romans under Sittas and Belisarius, succeeded in defeating them. At the same time, Licelarius, a Thracian in the Roman service, made an incursion into the tract about Nisibis, grew alarmed without cause and beat a speedy retreat. Hereupon Justin recalled him as incompetent, and the further conduct of the war in Mesopotamia was entrusted to Belisarius, who took up his headquarters at Daras.