Following the footsteps of the Xiongnu Empire and the successes of the Huns in Europe, Kok Turks established a strong state after crushing the Tieles and destroying the Avar Empire in 552 CE. After them, Uighurs established a large empire centered in Xinjiang and Mongolia and extending into Siberia, China, and Transoxiana. The Uighur Empire lasted almost a century and ended after long wars with the Tibetans and the Kyrgyz. Another Turkic empire was the Khazar Khanate, which ruled North Caucasia, the Ukraine, and southern Russia in the Volga region around the Caspian Sea.