Following the First Siege of Constantinople by the Avars and Persians, the beleaguered Byzantine Emperor Heraclius found himself politically isolated. He could not rely on the Christian Armenian potentates of Transcaucasia, since they were branded as heretics by the Orthodox Church, and even the king of Iberia preferred to befriend the religiously tolerant Persians. Against this dismal background, he found a natural ally in Tong Yabghu. Earlier in 568, the Turks under Istämi had turned to Byzantium when their relations with Persia soured over commerce issues. Istämi sent an embassy led by the Sogdian diplomat Maniah directly to Constantinople, which arrived in 568 and offered not only silk as a gift to Justin II, but also proposed an alliance against Sassanid Persia. Justin II agreed and sent an embassy to the Turkic Khaganate, ensuring the direct Chinese silk trade desired by the Sogdians.

In 625, Heraclius dispatched to the steppes his emissary, named Andrew, who promised to the Khagan some "staggering riches" in return for military aid. The khagan, on his part, was anxious to secure the Chinese-Byzantine trade along the Silk Route, which had been disrupted by the Persians in the aftermath of the Second Perso-Turkic War. He sent word to the Emperor that "I shall take revenge on your enemies and will come with my valiant troops to your help". A unit of 1,000 horsemen fought their way through Persian Transcaucasia and delivered the Khagan's message to the Byzantine camp in Anatolia.

The Third Perso-Turkic War was the third and final conflict between the Sassanian Empire and the Western Turkic Khaganate. Unlike the previous two wars, it was not fought in Central Asia, but in Transcaucasia. Hostilities were initiated in 627 CE by Tong Yabghu Qaghan of the Western Göktürks and Emperor Heraclius of the Byzantine Empire. Opposing them were the Sassanid Persians, allied with the Avars. The war was fought against the background of the last Byzantine-Sassanid War and served as a prelude to the dramatic events that changed the balance of powers in the Middle East for centuries to come.

In April 630 Böri Shad determined to expand his control of Transcaucasia and sent his general Chorpan Tarkhan with as little as 30,000 cavalry to invade Armenia. Using a characteristic ploy of nomadic warriors, Chorpan Tarkhan ambushed and annihilated a Persian force of 10,000 dispatched by Shahrbaraz to counter the invasion. The Turks knew the Sassanid response would be harsh, and so they plundered cities and withdrew their forces back to the steppes.