The region of Transoxiana had been conquered by the Muslim Arabs of the Umayyad Caliphate under Qutayba ibn Muslim in the reign of al-Walid I (r. 705–715), following the Muslim conquests of Persia and Khurasan in the mid-7th century.[2][3] The loyalties of Transoxiana's native Iranian and Turkic populations and those of autonomous local rulers remained questionable, however, as demonstrated in 719, when the Transoxianian princes sent a petition to the Chinese and their Türgesh vassals for military aid against the Caliphate's governors.[4] The Türgesh responded by launching a series of attacks against the Muslims in Transoxiana, beginning in 720. These incursions were coupled with uprisings against the Caliphate among the local Sogdians.