From his father, Hormizd had inherited an
ongoing war against the
East Roman (Byzantine) Empire. Negotiations of peace had just begun with the Emperor
Tiberius II, who offered to give up all claims to
Armenia and interchange the Byzantine-occupied
Arzanene for the Iranian-occupied
Dara (which was an important Byzantine stronghold). Hormizd, however, further demanded the payment of the yearly tribute that was made during the reign of
Justinian I (), and thus caused the negotiations to be broken off. No campaign in
Mesopotamia was undertaken by either of the empires due to the negotiations, however they continued to clash in Armenia, where
Varaz Vzur succeeded
Tamkhosrow as the new Sasanian governor of Armenia. The Byzantines were successful at their endeavors, securing a noteworthy victory under the commanders
Cours and
John Mystacon, albeit also suffering a defeat at the hands of the Sasanians. In early 580, the clients and vassals of the Sasanians, the
Lakhmids, were defeated at the hands of the
Ghassanids, vassals of the Byzantines. In the same year, a Byzantine army ravaged
Garamig ud Nodardashiragan, reaching as far as
Media. Around the same time,
Bakur III, the Sasanian client king of
Iberia, died, leaving behind two sons who were underage. Hormizd took advantage of the situation by abolishing the Iberian monarchy, i.e. the
Chosroid dynasty. He appointed his son Khosrow as the governor of
Caucasian Albania, who negotiated with the Iberian aristocracy and won their support, so successfully incorporating the country into the Sasanian Empire. The following year (581), an ambitious campaign by the Byzantine commander
Maurice, supported by Ghassanid forces under
al-Mundhir III, targeted the Sasanian capital of
Ctesiphon. The combined force moved south along the river
Euphrates, accompanied by a fleet of ships. The army stormed the fortress of
Anatha and moved on until it reached the region of
Beth Aramaye in central Mesopotamia, near Ctesiphon. There they found the bridge over the Euphrates destroyed by the Iranians. In response to Maurice's advance, the Iranian general
Adarmahan was ordered to operate in northern Mesopotamia, threatening the Byzantine army's supply line. Adarmahan raided
Osrhoene, and was successful in capturing its capital,
Edessa. He then marched his army toward
Callinicum on the Euphrates. With the possibility of a march to Ctesiphon gone, Maurice was forced to retreat. The retreat was arduous for the tired army, and Maurice and al-Mundhir exchanged recriminations for the expedition's failure. However, they cooperated in forcing Adarmahan to withdraw and defeated him at Callinicum. Tiberius tried afterwards to renew negotiations by sending Zachariah to the frontier to meet Andigan. The negotiations broke off once more after Andigan attempted to pressure him by drawing the attention of the nearby Iranian contingent led by Tamkhosrow. In 582, Tamkhosrow, along with Adarmahan, invaded Byzantine territory and headed for the town of
Constantina. Maurice, who had been expecting and preparing for such an attack, fought the Iranians outside the city in June 582. The Iranian army suffered a heavy defeat, and Tamkhosrow was killed. Not long afterwards, the deteriorating physical condition of Tiberius forced Maurice to return immediately to
Constantinople to assume the crown. Meanwhile, John Mystacon, who had replaced Maurice as the Commander of the East, attacked the Sasanians at the junction of the
Nymphius and the
Tigris, but was defeated by the Iranian general
Kardarigan. of the
Byzantine emperor
Maurice () In 583, the objective of the Iranian army was to recapture the fortress
Aphumon, which had been seized by Maurice in 578. However, while they besieged the fortress, the Romans besieged
Akbas, a newly constructed fortress east of the Nymphius and thus close to the Roman frontier. This diverted the attention of the Iranian soldiers at Aphumon, who went to relieve Akbas. By the end of year, however, the Romans had destroyed the fortress. Hormizd then sued for peace: in 584, an Iranian envoy arrived at Constantinople, while a Roman envoy arrived at Ctesiphon. The negotiations, however, broke off once again. Around the same time,
Philippicus was appointed the new Commander of the East. In 585, Kardarigan went on the offensive, besieging the Byzantine base of
Monocarton. The siege failed, and he then marched north to
Martyropolis, Philippicus's base; after sacking the church of
John the Baptist near the city, however, he returned to Iranian territory, most likely Armenia. In the spring of 586, Hormizd once again attempted to make peace, and sent
Mahbod to negotiate with Philippicus at
Amida. Negotiations, however, broke down once more after the Iranians demanded gold in exchange for peace. Not long after, an Iranian force—led by Kardarigan, Aphraates and Mahbod—suffered a heavy defeat against the Byzantines at the
Battle of Solachon. The victory was followed by destructive raids into
Corduene and
Arbayistan. In the following year, the new commander of the east,
Heraclius the Elder, captured three fortresses near Dara. The Iranians took advantage of the discord in the Roman army between 588 and 589, and managed to successfully occupy Martyropolis in 589 with the help of a
turncoat Roman officer. == Turkic incursions in the east ==