This was much to the dislike of Khosrow, who considered the Turkic collaboration with the Hephthalites to pose a danger for his rule in the east, and thus marched towards the Sasanian-Turkic border in Gurgan. When he reached the place, he was met by a Turkic delegate of Sinjibu that presented him gifts. There Khosrow asserted his authority and military potency, and persuaded the Turks to make an alliance with him. The alliance contained a treaty that made it obligatory for Faghanish to be sent to the Sasanian court in Ctesiphon and gain the approval of Khosrow for his status as Hephthalite king. Faghanish and his kingdom of Chaghaniyan thus became a vassal of the Sasanian Empire, which set the Oxus as the eastern frontier the Sasanians and Turks. However, friendly relations between Turks and Sasanians quickly deteriorated after that. Both Turks and Iranians wanted to dominate the Silk Road and the trade industry between the west and the far east. In 562 Khosrow II defeated the Hephthalites once again, and then stopped the threat of the Turks.
this was much to the dislike of khosrow who considered the turkic collaboration with the hephthalites to pose a danger for his rule in the east and thus marched towards the sasanian-turkic border in gurgan when he reached the place he was met by a turkic delegate of sinjibu that presented him gifts there khosrow asserted his authority and military potency and persuaded the turks to make an alliance with him the alliance contained a treaty that made it obligatory for faghanish to be sent to the sasanian court in ctesiphon and gain the approval of khosrow for his status as hephthalite king faghanish and his kingdom of chaghaniyan thus became a vassal of the sasanian empire which set the oxus as the eastern frontier the sasanians and turks however friendly relations between turks and sasanians quickly deteriorated after that both turks and iranians wanted to dominate the silk road and the trade industry between the west and the far east in 562 khosrow ii defeated the hephthalites once again and then stopped the threat of the turks