The oldest written records are found upon stone monuments in Central Asia, in the Orhon, Yenisey and Talas regions within the boundaries of present-day Mongolia. These were erected to Bilge Kaghan (735), Kültigin (732), and the vizier Tonyukuk (724-726). These monuments document the social and political life of the Gokturk Dynasty.
After the waning of the Gokturk state, the Uighurs produced many written texts that are among the most important source works for the Turkish language. The Uighurs abandoned shamanism (the original Turkish religion) in favor of Buddhism, Manichaeanism and Brahmanism, and translated the pious and philosophical works into Turkish. Examples are Altun Yaruk, Mautrisimit, Sekiz Yükmek, Huastunift. These are collected in Turkische Turfan-Texte. The Gokturk inscriptions, together with Uighur writings, are in a language called by scholars Old Turkish. This term refers to the Turkish spoken, prior to the conversion to Islam, on the steppes of Mongolia and Tarim basin.