What is tian kehan?

Tian Kehan

Tian Kehan (Chinese: 天可汗; pinyin: Tiān Kěhán; Wade–Giles: T'ien K'ehan) also translated as Heavenly Khagan, Celestial Khagan or Tengri Khagan, was a title addressed to Emperor Taizong of Tang by various Turkic nomads. It was first mentioned in accounts on May 20, 630 and again on October 24, 646, shortly after the Eastern Turkic Khaganate and Xueyantuo were annihilated by Emperor Taizong's generals.

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