Byzantine-Sasanian War of 602-628: Heraclius Against Persia

The Byzantine-Sasanian War of 602–628 was the last and most destructive conflict between the Eastern Roman (Byzantine) Empire and Sasanian Persia. For nearly two decades the Persians under Khosrow II seemed close to destroying Byzantium, conquering Syria, Jerusalem and Egypt and camping opposite Constantinople. Then Emperor Heraclius launched a daring counteroffensive deep into Persian territory, culminating near Nineveh in 627. The war ended in Byzantine victory, but it left both empires exhausted just before the Arab conquests.

Causes

Rome and Persia had fought on and off for centuries along a frontier running through Armenia and Mesopotamia. In 590 a revolt drove the young Persian king Khosrow II from his throne, and he fled to Roman territory. The Byzantine emperor Maurice helped him regain power in 591, receiving much of Armenia in return. A period of peace followed.

In November 602 the Byzantine army on the Danube mutinied and proclaimed the junior officer Phocas emperor. Maurice and his sons were executed. Khosrow declared war, presenting himself as Maurice’s avenger and supporting a man said to be Maurice’s son Theodosius. Phocas also faced a revolt by the general Narses at Edessa, which further weakened the eastern defences.

Persian victories, 603–622

Persian armies first broke through in Mesopotamia, taking the fortress of Dara after a long siege around 604–605, and then pushed into Armenia and eastern Anatolia. Phocas’s rule became increasingly violent and unstable.

In 610 Heraclius, son of the governor of Africa, sailed from Carthage, overthrew Phocas and was crowned emperor on 5 October 610. His early years brought only further disasters. In 613 the Persians defeated him near Antioch and took Damascus. In 614 the general Shahrbaraz captured Jerusalem after a siege of about three weeks. Contemporary Christian sources report many thousands of deaths and the deportation of the patriarch, and the relic of the True Cross was taken to the Persian capital Ctesiphon.

Egypt, the empire’s main source of grain, fell between about 618 and 621. Persian forces under Shahin reached Chalcedon, across the Bosporus from Constantinople, around 615–616. At the same time the Avars and Slavs ravaged the Balkans. The empire was reduced to Anatolia, parts of the Balkans, North Africa and fragments of Italy.

Heraclius strikes back, 622–626

Heraclius reorganised finances, melted down church plate with the agreement of the patriarch Sergius, and rebuilt his army. In 622 he campaigned in Anatolia and defeated Shahrbaraz. Instead of trying to recover the lost provinces directly, he chose to strike at Persia’s heartland through Armenia and the Caucasus.

In 624 he invaded Persian Azerbaijan and destroyed the great fire temple of Adur Gushnasp, one of the holiest sites of the Zoroastrian religion. He fought a series of campaigns in 624–626, often outnumbered, relying on speed and alliances with Caucasian peoples.

In 626 Khosrow tried to end the war by attacking Constantinople itself in cooperation with the Avars. The plan failed (see Siege of Constantinople, 626), and Heraclius’s brother Theodore defeated another Persian army in Anatolia.

Nineveh and the fall of Khosrow, 627–628

Heraclius allied with the Western Turks, who joined him to besiege Tiflis (Tbilisi) in 627. Late that year he marched south into Mesopotamia. On 12 December 627 he defeated a Persian army under the general Rhahzadh near the ruins of ancient Nineveh, close to modern Mosul; the Persian commander was killed.

Heraclius then advanced towards Ctesiphon and sacked Khosrow’s palace at Dastagerd in early 628. Khosrow’s position collapsed. In February 628 he was overthrown by his son Kavad II (Sheroe) and put to death. Kavad sued for peace, agreeing to return all conquered territory, prisoners and the True Cross. Kavad died later that year, and Persia slid into civil war, with several rulers in quick succession.

Key people

Heraclius (reigned 610–641) came from an Armenian-descended family and grew up in North Africa, where his father governed. His counteroffensive of 622–628, fought largely in person far from his capital, was one of the boldest campaigns of the Middle Ages. His later reign, however, saw the loss of Syria and Egypt to the Arabs.

Khosrow II (reigned 590 and 591–628), known in Persian tradition as Khosrow Parviz (“the Victorious”), presided over the greatest expansion of the Sasanian Empire since the days of the ancient Achaemenid kings. His refusal to make peace when he held the upper hand, and his heavy taxation to fund the war, contributed to his downfall.

Shahrbaraz was the most successful Persian general of the war, conqueror of Jerusalem and Egypt. Relations between him and Khosrow broke down in the late 620s. After the peace he negotiated the Persian evacuation of Byzantine lands with Heraclius and briefly seized the Persian throne in 630 before being murdered.

Patriarch Sergius I of Constantinople supported Heraclius financially and politically, allowing church treasures to be used for the war, and led the defence of the capital in 626.

A religious war

Contemporaries on both sides gave the war a strong religious character. The capture of the True Cross in 614 shocked the Christian world, and Byzantine propaganda, including the poems of George of Pisidia, presented Heraclius’s campaigns as a holy war against the fire-worshipping Persians. His destruction of the fire temple of Adur Gushnasp was a deliberate blow at the Zoroastrian faith of the Persian monarchy.

The conflict was also noticed in Arabia. The Quran’s thirtieth chapter, known as al-Rum (“The Romans”), refers to a Roman defeat in a nearby land and predicts that the Romans will be victorious within a few years. Muslim commentators traditionally link these verses to the Persian victories of the 610s and Heraclius’s later triumph.

By the numbers

Reliable army sizes and casualty figures do not survive; modern estimates vary widely and should be treated with caution.

Consequences

Heraclius returned in triumph and restored the True Cross to Jerusalem, an event later celebrated in Christian art. But the victory was hollow. The recovered provinces had been under Persian rule for years, their tax systems and garrisons disrupted. Religious divisions between Chalcedonian and non-Chalcedonian Christians remained deep.

In Persia, the defeat and Khosrow’s murder destroyed royal authority. Within a few years Arab Muslim armies, united under the early caliphate, attacked both empires. The Byzantines lost Syria after the Battle of Yarmouk in 636, and the Sasanians lost Iraq after the Battle of al-Qadisiyyah in 636 or 637. The war of 602–628 had cleared the way.

Timeline

• 602, November: Phocas overthrows Maurice; Khosrow II prepares for war.
• c. 604–605: The Persians capture Dara.
• 610, 5 October: Heraclius is crowned emperor after deposing Phocas.
• 614: Shahrbaraz captures Jerusalem and takes the True Cross.
• c. 618–621: Persian conquest of Egypt.
• 622: Heraclius begins his counteroffensive in Anatolia.
• 626, summer: Avar and Persian siege of Constantinople fails.
• 627, 12 December: Byzantine victory near Nineveh.
• 628, February: Khosrow II is overthrown; Kavad II makes peace.
• 630, 21 March: Heraclius restores the True Cross to Jerusalem (date debated).

Why it matters

The war was the climax of four centuries of Roman-Persian rivalry. Its outcome saved Byzantium, but the exhaustion it caused helps explain why the Arab conquests that followed were so rapid, reshaping the Middle East and the Mediterranean world.