 Since the beginning of the 9th century it had become Jiaohe prefecture of the Uyghur Khaganate, until their kingdom was conquered by the Kyrgyz soon after in the year 840.Yarkhoto was also built on a plateau and this plateau is 30m high.The city was built on a large islet (1650 m in length, 300 m wide at its widest point) in the middle of a river which formed natural defenses, which would explain why the city lacked any sort of walls.