Hephthalite Empire
In 557, Khosrow I (), the king ("shah") of the Sasanian Empire, who had greatly increased the authority of his empire, decided to put an end to the Hephthalite Empire domination over Central Asia. He thus allied with the Göktürks in order to defeat the Hephthalites. The campaign was successful and the region north of the Oxus went to the Turks whilst the south came under Sasanian rule. An agreement was established between Khosrow I and the Turkic Khagan Istämi which set the Oxus as the frontier between the two empires. However, in 588, the Turkic Khagan Bagha Qaghan (known as Sabeh/Saba in Persian sources), together with his Hephthalite subjects, invaded the Sasanian territories south of the Oxus, where they attacked and routed the Sasanian soldiers stationed in Balkh, and then proceeded to conquer the city along with Talaqan, Badghis, and Herat.