Under what dynasty did the regional military governors gain power?
The Tang dynasty was largely a period of progress and stability in the first half of the dynasty's rule, until the devastating An Lushan Rebellion (755-763) and the decline of central authority in the later half of the dynasty. Like the previous Sui dynasty, the Tang dynasty maintained a civil-service system by recruiting scholar-officials through standardized examinations and recommendations to office.  The rise of regional military governors known as jiedushi during the 9th century undermined this civil order.  Chinese culture flourished and further matured during the Tang era; it is traditionally considered the greatest age for Chinese poetry.  Two of China's most famous poets, Li Bai and Du Fu, belonged to this age, as did many famous painters such as Han Gan, Zhang Xuan, and Zhou Fang.  Scholars of this period compiled a rich variety of historical literature, as well as encyclopedias and geographical works. The adoption of the title Tängri Qaghan by the Tang Emperor Taizong in addition to his title as emperor was eastern Asia's first "simultaneous kingship".Many notable innovations occurred under the Tang, including the development of woodblock printing.  Buddhism became a major influence in Chinese culture, with native Chinese sects gaining prominence.  However, in the 840s the Emperor Wuzong of Tang enacted policies to persecute Buddhism, which subsequently declined in influence. Although the dynasty and central government had gone into decline by the 9th century, art and culture continued to flourish. The weakened central government largely withdrew from managing the economy, but the country's mercantile affairs stayed intact and commercial trade continued to thrive regardless. However, agrarian rebellions in the latter half of the 9th century resulted in damaging atrocities such as the Guangzhou massacre of 878–879.
Tang dynasty