The region of Transoxiana (Arabic: Ma wara' al-nahr) had been conquered by the Umayyad leader 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. 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 Turgesh vassals for military aid against the Caliphate's governors. The Turgesh 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. The Umayyad governor of Khurasan, Sa'id ibn Amr al-Harashi, hars