Emperor Taizong of Tang in 640 had …
Years: 692 - 692
Emperor Taizong of Tang in 640 had launched a campaign against the Western Regions and the Kingdom of Khotan had submitted to the Tang emperor.
The Four Garrisons of Anxi had been established, one of them at Khotan.
The Tibetans had subsequently defeated the Chinese and had taken control of the Four Garrisons, and the Khotanese had helped the Tibetans to conquer Aksu.
Tang China under Empress Wu in 692 regains control.
Khotan is made a protectorate.
