Jia Dan

Jia Dan (simplified Chinese: 贾耽; traditional Chinese: 賈耽; pinyin: Jiǎ Dān, 730 – 805), courtesy name Dunshi (敦詩) and formally Duke Yuanjing of Wei (魏元靖公), was a Chinese cartographer, military general, and politician from Cangzhou, Hebei during the Tang dynasty.

Jia Dan was born in 730, during the reign of Emperor Xuanzong. His family was from Cang Prefecture (滄州, in modern Cangzhou, Hebei) and traced its ancestry to the Han dynasty official Jia Yi, through officials of Cao Wei, Jin dynasty (266–420), Liu Song, Southern Qi, Liang dynasty, Northern Qi, Northern Zhou, Sui dynasty, and Tang dynasty. Both his grandfather Jia Zhiyi (賈知義) and father Jia Yuanyan (賈元琰) served as county-level officials.

During Emperor Xuanzong's Tianbao era (742–756), Jia Dan passed the imperial examinations and was made the sheriff of Linqing County (臨清, in modern Liaocheng, Shandong). After he submitted suggestions on the matters of the times to Emperor Xuanzong, he was moved to be the sheriff of Zhengping County (正平, in modern Yuncheng, Shanxi) — closer to the capital Chang'an, and therefore considered a promotion despite it being the same level of office. While the general Wang Sili (王思禮) served as the military governor (Jiedushi) of Hedong Circuit (河東, headquartered in modern Taiyuan, Shanxi), Wang invited him to serve as secretary. While serving under Wang, Jia was promoted to be the deputy mayor of Taiyuan Municipality and deputy military governor. He later served as the prefect of Fen Prefecture (汾州, in modern Linfen, Shanxi) for seven years and was known for ruling the prefecture well.

Jia was then recalled to Chang'an to serve as the minister of vassal affairs (鴻臚卿, Honglu Qing), which included the responsibilities of receiving and entertaining foreign emissaries, as well as imperial funerals and the command of two units of the imperial guards, the Weiyuan Camp (威遠營). As the minister of vassal affairs, he would have met with foreign envoys in order to acquire information about their native countries. This included cultural customs as well as geographic information, as a map was drawn after the geographic information was acquired from the interview. Historian Edward Schafer states that it is no doubt that Jia's remarkable knowledge of foreign geography was derived from these interviews with foreign delegates and diplomats. In 779, during the reign of Emperor Xuanzong's grandson Emperor Daizong, Jia was made the prefect of Liang Prefecture (梁州, in modern Hanzhong, Shaanxi) and the military governor of Shannan West Circuit (山南西道, headquartered at Liang Prefecture).

In 781, during the reign of Emperor Daizong's son Emperor Dezong, when Liang Chongyi, the military governor of nearby Shannan East Circuit (山南東道, headquartered in modern Xiangfan, Hubei), rebelled against Emperor Dezong's rule, Jia Dan participated in the campaign against Liang and captured Jun Prefecture (均州, in modern Shiyan, Hubei). In 782, after Liang's defeat and suicide, Jia was made the military governor of Shannan East Circuit, and in 783 participated in the campaign against another rebel general, Li Xilie the military governor of Huaixi Circuit (淮西, headquartered in modern Zhumadian, Henan.

In 784, while Emperor Dezong was at Liang Prefecture after he fled there due to rebellions by the general Zhu Ci and Li Huaiguang, there was an occasion when Jia sent his officer Fan Ze (樊澤) to make reports to Emperor Dezong. After Fan's return, there was suddenly an imperial edict issued making Fan the military governor of Shannan East Circuit and recalling Jia to Emperor Dezong's location to serve as the minister of public works (工部尚書, Gongbu Shangshu). When the edict arrived, Jia was hosting a feast, and he received the edict as if nothing had happened. After the feast was over, he informed Fan of his promotion and immediately began the transition, including having the other officers greet Fan as their new superior. The officer Zhang Xianfu (張獻甫) was angered, believing that Fan had treacherously seized Jia's position, and he wanted to kill Fan. Jia stopped him, pointing out that because Fan had imperial sanction, he was the proper military governor. That same day, he left his post and headed for the emperor's location, taking Zhang with him to avoid any further disturbance. Jia was soon made the defender of the eastern capital Luoyang.

In 786, after the death of Li Cheng (李澄) the military governor of Yicheng Circuit (義成, headquartered in modern Anyang, Henan), Jia was made the military governor of Yicheng. At that time, Li Na the military governor of neighboring Pinglu Circuit (平盧, headquartered in modern Tai'an, Shandong), who had previously rebelled against Emperor Dezong but later resubmitted (albeit nominally), was still viewed as a threat to the circuits loyal to the imperial regime. On an occasion, when Pinglu soldiers, returning from a posting to the western border with Tufan, were going through Yicheng on the way back to Pinglu, Jia's subordinates, worried that they might act against Yicheng, suggested that they be kept outside the city walls of Yicheng's headquarters Hua Prefecture (滑州). Jia, reasoning that it was improper to let soldiers from a neighboring circuit rest in the open air, welcomed them inside, and the Pinglu soldiers did not dare to create any disturbance. Jia also often hunted on the borders with Pinglu, often venturing into Pinglu territory. When Li Na received these reports, he was pleased that Jia did not consider him hostile and admired Jia for his openness, and therefore did not carry out any hostile actions against Yicheng.

In 793, Jia was recalled to Chang'an to serve as You Pushe (右僕射), one of the heads of the executive bureau of government (尚書省, Shangshu Sheng). He was also given the designation Tong Zhongshu Menxia Pingzhangshi (同中書門下平章事), making him a chancellor, serving with Lu Zhi (Tang dynasty), Zhao Jing, and Lu Mai.