By: Mir M.Hosseini
The battle fought in Nineveh was the peak of a series of battles that had started in 622 by the Roman Empire to push back Iranians to their original boundaries. In 602 Khosrau Parviz had begun a long war against the Byzantine Empire and by 619 had conquered almost all southwestern Asia Minor and Egypt. In an alliance with Gokturks and Khazars, Heraclius leaded the Nineveh battle which had started with an unsuccessful siege of Tbilisi. The Iranian army was defeated under commander Rahazad who was killed in the battlefield. One year later Iranians accepted terms for peace proposed by Heraclius in disgrace. The downfall of the empire accelerated with the Arab invasion in 636.
When Emperor Maurice was murdered by the usurper Phocas, Khosrau 2 declared war, ostensibly to avenge his benefactor's death. While the Persians proved largely successful during the first stages of the war, conquering much of Egypt and Anatolia, the ascendancy of Heraclius eventually led to the Persian demise. Heraclius' campaigns altered the balance, forcing the Persians on the defensive and allowing for the Byzantines to regain momentum. Allied with the Avars, the Persians attempted to take Constantinople, but were defeated there.
While the Siege of Constantinople was taking place, Heraclius allied with what Byzantine sources called the Khazars, who are identified with the Western Turkic Khaghans of the Gokturks: plying him with gifts and promise of rewards. The Caucasus-based Turks responded by sending 40,000 of their men to avenge the Persian Empire which held nomads at bay at all times. Joint Byzantine and Gokturk operations were focused on besieging Tbilisi.
In mid-September 627, leaving Gokturks to continue the siege of Tbilisi, Heraclius invaded the Persian heartland, this time with between 25,000 and 50,000 troops and 40,000 Gokturks. The Gokturks, however, quickly deserted him because of the strange winter conditions. Heraclius was tailed by Rahazad's army of 12,000, but managed to evade Rahazad and invaded the heartland of Persia, in Iraq. Heraclius acquired resources from the countryside, which meant the following Rahazad had trouble acquiring provisions. This resulted in harm to Rahazad's animals.
Both Heraclius and the Persians approached from the east of Nineveh. Persian reinforcements were near Mosul. After the battle, Heraclius went back east while the Persians looped back to Nineveh itself before following Heraclius again.
On December, 1 Heraclius crossed the Great Zab River and camped near Nineveh. This was a movement from south to north, contrary to the expectation of a southward advance. However, this can be seen as a way to avoid being trapped by the Persian army in case of a defeat. Rahazad approached Nineveh from a different position. News that 3,000 Persian reinforcements were approaching reached Heraclius, forcing him to act. He gave the appearance of retreating from Persia by crossing the Tigris.
Heraclius had found a plain west of the Great Zab some distance from the ruins of Nineveh.
Rahazad deployed his forces into three masses and attacked. Heraclius feigned retreat to lead the Persians to the plains before reversing his troops to the surprise of the Persians. After eight hours of fighting, the Persians suddenly retreated to nearby foothills, but it was not a rout. 6,000 Persians fell on Dec, 12, 627.
Nikephoros' Brief History mentions that Rahazad challenged Heraclius to personal combat. Heraclius accepted and killed Rahazad in a single thrust; two other challengers fought and also lost. But either way, Rahazad died sometime in the battle.
The 3,000 Persian reinforcements arrived too late and likely joined with the remnants of Rahazad's force.
The Battle of Nineveh was the climactic battle of the Byzantine-Sassanid War of 602-628. The Byzantine victory broke the power of the Sassanid dynasty and for a period of time restored the empire to its ancient boundaries in the Middle East.
The victory at Nineveh was not total as the Byzantines were unable to capture the Persian camp. However, this victory was significant enough to shatter the resistance of the Persians.
With no Persian army left to oppose him, Heraclius' victorious army plundered Dastgerd, Khosrau's palace, and gained tremendous riches while recovering 300 captured Byzantine and Roman standards accumulated over years of warfare. Khosrau had already fled to the mountains of Susiana to try to rally support for the defense of Ctesiphon. Heraclius could not attack Ctesiphon itself because the Nahrawan Canal was blocked due to the collapse of a bridge leading over it.
The Persian army rebelled and overthrew Khosrau 2, raising his son Kavadh 2nd, also known as Siroes, in his stead. Khosrau perished in a dungeon after suffering for five days on bare sustenance-he was shot to death slowly with arrows on the fifth day. Kavadh immediately sent peace offers to Heraclius. Heraclius did not impose harsh terms, knowing that his own empire was also near exhaustion. Under the peace treaty, the Byzantines regained all their lost territories, their captured soldiers, a war indemnity, and of great spiritual significance, the True Cross and other relics that were lost in Jerusalem in 614.
This loss was followed by internal conflicts and conspiracies within the Persian royal family leading to public discontent to the extent that tribal Arabs won battles against the Sassanid army leading to downfall of the Sassanid Empire