The Göktürk Khaganate was a powerful confederation of Turkic peoples spanning a vast region of central Asia from c. 522 to 659. It interacted extensively with the settled civilizations of China and Persia and for a long time exercised control over the valuable Silk Road trade route.
In the mid-7th century the Göktürks were defeated and subjugated by Emperors Taizong and Gaozong of Tang China. At first the majority of their leaders were willing to swear allegiance to Tang, but as Gaozong's health deteriorated and his rule weakened, a number of tribes broke out into open rebellion against China. Eventually, when they saw they could not defeat China, a number of tribes came together to form a new confederacy and migrated away to the west beyond Chinese control.
In 665 the confederacy invaded Persia, but was defeated with heavy losses. Instead it decided to continue making its way north and west, eventually ending up between the Hyrcanian and Euxine Seas where it merged with the Khazars, another Turkic people who had already been living in the area for decades.
Yet another group of Turks, the Bulgars, dwelt on the northern shore of the Euxine, and had a deadly rivalry with the Khazars. When their Khan Kubrat died in 668, the Khazars took the opportunity to invade and destroy Old Great Bulgaria. The Bulgar nation almost disintegrated, but Khan Asparukh managed to hold them together to found a new empire in the Balkans.
Khazaria took over the western steppes until it eventually fell to the Rus in 1048.