Persia and the Eastern Roman Empire had agreed on a seven-year truce after the Anastasian War ended in 506, yet it has lasted for nearly twenty years.

Even during the war in 505, Emperor Anastasius I had already started fortifying Dara as a counter to the Persian fortress city of Nisibis for a looming conflict.

In 524, the Persian shah Kavadh I proposes that Emperor Justin I adopt his son, Khosrau I; the priority of the Persian king is to secure the succession of Khosrau, whose position is threatened by rival brothers and the Mazdakite sect.

The proposal is initially greeted with enthusiasm by the Roman Emperor and his nephew, Justinian, but Justin's quaestor, Proculus, opposes the move.

Despite the breakdown of the negotiations, it will not be until 530 that full-scale warfare on the main eastern frontier breaks out.

In the intervening years, the two sides will prefer to wage war by proxy, through Arab allies in the south and Huns in the north.

The Persians begin intruding upon Roman Mesopotamian territory in 524, provoking a succession of border skirmishes.

Tensions between the two powers are further heightened by the defection of the Iberian king Gourgen to the Romans.

According to Procopius, Kavadh tried to force the Christian Iberians to become Zoroastrians, who in 524/525 under the leadership of Gourgen rise in revolt against Persia, following the example of the neighboring Christian kingdom of Lazica.

Gourgen receives pledges by Justin I that he will defend Iberia; the Romans indeed recruit Huns from the north of the Caucasus to assist the Iberians.

Violence escalates at various points where the power of the two empires meet: in 525 a Roman fleet had transported an Aksumite army to conquer Himyarite Yemen and in 525/526, Persia's Arab allies, the Lakhmids, raid Roman territories on the edge of the desert.

Kavadh, assisted by his Arabian vassal, Al-Mundhir III, begins a campaign in the Transcaucasus region and Upper Mesopotamia.

Overt Roman–Persian fighting had broken out in the Transcaucasus region and upper Mesopotamia by 526–527.

The early years of war favor the Persians: by 527, the Iberian revolt has been crushed, a Roman offensive against Nisibis and Thebetha in this year is unsuccessful, and forces trying to fortify Thannuris and Melabasa are prevented from doing so by Persian attacks.

Attempting to remedy the deficiencies revealed by these Persian successes, the new Roman emperor, Justinian I, reorganizes the eastern armies.

The Persians press on from Iberia to capture forts in eastern Lazica in 528.

Attempting to remedy the deficiencies revealed by these Persian successes, Justinian reorganizes the eastern armies by dividing the command of the magister militum of the East in two and appointing a separate magister militum of Armenia over the northern portion.

Procopius of Caesarea, Palestine-born and trained in law, serves Justinian’s general Belisarius as legal advisor from 527, accompanying him on his campaigns.

The most important Roman initiative on the southern front in 528 is Belisarius's expeditions to Thannuris, where he tries unsuccessfully to protect Roman workers, undertaking the construction of a fort right on the frontier.

The Sassanid crown prince, Khosrau, an orthodox Zoroastrian, collaborates with the chief mobed to contrive the condemnation of the Mazdakites.

In 528, Kavadh has them assemble as if for a meeting and then massacres them.

By this time, the Nestorian doctrine (claiming that divine and human persons remained separate in the incarnate Christ) has become dominant among the Christians in Iran and is definitely established as the accepted form of Christianity in the Sassanian Empire.

Damaging raids on Syria by the Lakhmids in 529 also encourage Justinian to strengthen his own Arab allies, helping the new Ghassanid leader al-Harith ibn Jabalah to turn a loose coalition into a coherent kingdom that will be able to gain the upper hand against the Lakhmids over the following decades.

In this capacity, Harith will fight on behalf of the Romans in all their numerous wars against Persia.

Already in 528, he had been one of the commanders sent in a punitive expedition against Mundhir.

In 529, he helps suppress the wide-scale Samaritan revolt, capturing twenty thousand boys and girls, who he sells as slaves.

It is perhaps Harith's successful participation in this conflict that leads Justinian to promote him to supreme phylarch.

Belisarius, in response to a major Persian offensive in 530, leads the Romans to victory over a much larger Persian force under Mihran through his superior generalship in the Battle of Dara, brilliantly deploying offensive cavalry and defensive infantry to defeat a combined Persian-Arab army of forty thousand.

It is possible that Al-Harith took part with his men in the Roman victory at Daras in 530, although no source explicitly mentions him.

At the same time, …

…Sittas and Dorotheus, commanding a cavalry force of thirty thousand troops, defeat a second Persian thrust in the Caucasus under Mihr-Mihroe at Satala.

Khosrau, a patron of learning, invites to his court Greek philosophers, their Academy in Athens having been shut down by Justinian in 529.