harvest tax was one-half the standard rate, an acknowledgement of the political problems inherent in ruling a non-Chinese population. In 687, the new governor of Annan, Liu Yanyou doubled the taxes. The indigenous peasants under chief Lý Tự Tiên resisted. Liu Yanyou killed Lý. Đinh Kiến, one of Lý's compatriots, led the people against Yanyou and besieged him in Songping. In the summer, the rebels took Songping and put Yanyou to death. A governor general, Feng Yuanchang, had earlier been called in to help Liu, but Feng hoped to gain influence at Liu's expense and did nothing to help him. Instead Feng established a fortified camp and sent envoys to the rebels telling them to kill their leader and join him. After Liu was killed, Feng abandoned Annan. Another general, Cao Xuanjing, marched into Annan, put down the rebellion, and executed Đinh Kiến. In 722, Mai Thúc Loan rebelled in what is now Hà Tĩnh Province and proclaimed himself the "Swarthy Emperor" or "Black Emperor" (Hắc Đẽ). His rebellion rallied people from 23 counties with "400,000 followers". Many were peasants who roamed the countryside, plundering food and other items. He also allied with Champa and Chenla, an unknown kingdom named Jinlin (“Gold Neighbor”) and other unnamed kingdoms. A Chinese army of 100,000 from Guangdong under general Yang Zixu, including a "multitude" of mountain tribesmen who had remained loyal to the Tang, marched directly along the coast, following the old road built by Ma Yuan. Yang Zixu attacked Mai Thúc Loan by surprise and suppressed the rebellion in 723. The corpses of the Swarthy Emperor and his followers were piled up to form a huge mound and were left on public display to check further revolts. In 767, a Javanese raiding fleet invaded Annan, besieging Songping, but were defeated by Tang marquis Zhang Boyi. In 785, chieftains of the Annamese, Đỗ Anh Hàn, Phùng Hưng and Phùng An rebelled, due to Chinese governor Gao Zhengping's doubling of taxes. Tang forces retook Annan in 791. In 803, a northern state of Champa, Huanwang, seized southern Annan. Tang troops working on garrison fortifications also revolted. From 803 to 863, local rebels killed or expelled no fewer than six protector-generals of Annan. In 820, Dương Thanh (Yang Qing) rebelled, seized Đại La, and killed the protectorate general. Dương Thanh was unpopular due to his cruelty and put to death by the locals soon after,