In 677 (during the reign of Emperor Gaozong), Chen Zheng (陳政), together with his son Chen Yuanguang (陳元光), led a military expedition to pacify the rebellion in Fujian. They settled in Zhangzhou and brought the Middle Chinese phonology of northern China during the 7th century into Zhangzhou; In 885, (during the reign of Emperor Xizong of Tang), the two brothers Wang Chao (王潮) and Wang Shenzhi (王審知), led a military expedition force to pacify the Huang Chao rebellion. They brought the Middle Chinese phonology commonly spoken in Northern China into Zhangzhou. These two waves of migrations from the north generally brought the language of northern Middle Chinese into the Fujian region. This then gradually evolved into the Zhangzhou dialect.
What country did Chen Yuanguang rule in 677?