Heraclius' Göktürk allies quickly deserted, while Rhahzadh's reinforcements did not arrive in time.

The Byzantine victory later resulted in civil war in Persia, and for a period of time restored the (Eastern) Roman Empire to its ancient boundaries in the Middle East.

When Emperor Maurice was murdered by the usurper Phocas, Khosrow II declared war under the pretext of avenging his benefactor's death.

[5] While the Siege of Constantinople was taking place, Heraclius allied with what Byzantine sources called the Khazars under Ziebel, who are identified with the Western Turkic Khaganate of the Göktürks led by Tong Yabghu,[6] plying him with wondrous gifts and a promise of the reward of the porphyrogenita Eudoxia Epiphania.

The Caucasus-based Turks responded by sending 40,000 of their men to invade the Caucasus in 626, inciting the Perso-Turkic war of 627–629.

[8] In mid-September 627, leaving Ziebel to continue the Siege of Tbilisi, Heraclius invaded the Persian Empire, this time with between 25,000 and 50,000 troops and 40,000 Göktürks.

[9][10] On 1 December, Heraclius crossed the Great Zab River and camped near the ruins of the capital of the former Assyrian Empire of Nineveh in Persian ruled Assyria/Assuristan.

Furthermore, fog reduced the Persian advantage in missile-shooting soldiers and allowed the Byzantines to charge without great losses from missile barrages.

Heraclius accepted and killed Rhahzadh in a single thrust; two other challengers fought and also lost.