The Chinese Buddhist pilgrim Xuanzang visited the western Göktürk capital Suyab in modern Kyrgyzstan and left a description of the khagan. Scholars believe the khagan described by Xuanzang was Tong Yabghu.
The historical record of Xuanzang's visit to Suyab highlights the significance of the khagan, who is now widely accepted by scholars as being Tong Yabghu.