Orkhon inscriptions

The Orkhon inscriptions are two memorial installations erected by the Göktürks written in the Old Turkic alphabet in the early 8th century in the Orkhon Valley in what is modern-day Mongolia. They were erected in honor of two Turkic princes, Kul Tigin and his brother Bilge Khagan.

The inscriptions, in both Chinese and Old Turkic, relate the legendary origins of the Turks, the golden age of their history, their subjugation by the Tang dynasty, and their liberation by Ilterish Qaghan. According to one source, the inscriptions contain "rhythmic and parallelistic passages" which resemble that of epics.

Source: Wikipedia