The rise of the collection of Oirat clans into what became known as the Zunghar Khanate in the 1600s saw much of what is now southern Kazakhstan leave the control of the Kazakh Khans. The historian Barthold argued that only after Galdan Boshugtu Khan, the Khong Tayiji of the Zunghars, had successfully conquered and destroyed the power of Sayram did he move his encampment west to the valley of the Ili, ensuring his control of Zhetysu east of Sayram. Galdan sent forces against Sayram in 1681, which must have been unsuccessful because they returned in 1683, when Barthold tells us that his commander Rabtan (probably Tsewang Rabtan took the city and razed it.