Cen Xi (岑羲) (d. July 29, 713), courtesy name Bohua (伯華), was an official of the Chinese dynasty Tang Dynasty and Wu Zetian's Zhou Dynasty, serving as a chancellor during the reigns of Emperor Shang, Emperor Ruizong, and Emperor Xuanzong. He was known for his integrity as an official in charge of civil service affairs, but was later implicated as a partisan of Emperor Xuanzong's aunt Princess Taiping in 713 and was executed when Emperor Xuanzong suppressed Princess Taiping's party.
Cen Xi himself passed the imperial examinations sometime before 691 and served as Taichang Boshi (太常博士), an official at the ministry of worship. In 691, during the reign of Emperor Taizong's daughter-in-law (and one-time concubine) Wu Zetian, who had declared a new Zhou Dynasty and interrupted Tang Dynasty, Cen Xi's uncle Cen Changqian, then a chancellor, was accused of treason and executed. As a result, Cen Xi was demoted to be a legal officer at Chen Prefecture (郴州, roughly modern Chenzhou, Hunan). He was subsequently made the magistrate of Jintan County. At that time, his brother Cen Zhongxiang (岑仲翔) was the magistrate of nearby Changzhou County (長洲, in modern Suzhou, Jiangsu) and another brother Cen Zhongxiu (岑仲休) was the magistrate of Lishui County (溧水, in modern Nanjing, Jiangsu). All three were known for their abilities in governance. The chancellor Zong Chuke, when an official was sent to examine the governance of the circuit containing those three counties, made the comment, "Do not forget about the three Cens east of the Yangtze River." He subsequently recommended Cen Xi, and Cen Xi was made the magistrate of Sishui County, near the capital Luoyang -- which was considered a major promotion due to its location.
As of 704, Cen Xi was serving as the magistrate of Guangwu County (廣武 -- the new name for Sishui), when Wu Zetian asked the chancellors to recommend officials suitable of serving as low level officials in various ministries. The chancellor Wei Sili recommended Cen, but commented, "Alas, his uncle was Cen Changqian, and he suffers from the taint." Wu Zetian responded, "As long as he is capable, what taint can there be?" She therefore made Cen Tianguan Yuanwailang (天官員外郎), an official at the ministry of civil service affairs. It was said that based on Cen's precedent, thereafter family members of officials previously killed during Wu Zetian's reign were able to begin getting promoted.
Less than a month later, Princess Taiping and Li Dan's son Li Longji the Prince of Linzi rose in rebellion and killed Empress Dowager Wei and Li Guo'er. Under their support, Li Dan, himself a former emperor, returned to the throne (as Emperor Ruizong), displacing Emperor Shang. Cen was made You Sanqi Changshi (右散騎常侍, a senior advisor at the legislative bureau) and minister of justice (刑部尚書, Xingbu Shangshu), and later demoted to be the prefect of Shan Prefecture (陝州, roughly modern Sanmenxia, Henan). He was, however, soon recalled to be the minister of census (戶部尚書, Hubu Shangshu). In 712, he was made chancellor de facto again, with the greater designation of Tong Zhongshu Menxia Sanpin (同中書門下三品). He was put in charge of editing the imperial history and also the register of clans. In editing the chronicles of Emperor Zhongzong's reign, he recorded how he and Xiao Zhizhong had spoken in Emperor Ruizong's defense when Li Chongjun's coup attempt occurred, and when Emperor Ruizong read the records, Emperor Ruizong thanked Cen and awarded him with silk and a good horse; Emperor Ruizong also made him Shizhong (侍中), the head of the examination bureau (門下省), a post considered one for a chancellor. Emperor Ruizong also created him the Duke of Nanyang.
At that time, Cen Xi's older brother Cen Xian (岑獻) was the deputy principal of the imperial university, and his younger brothers Cen Zhongxiang and Cen Zhongxiu were prefectural prefects. Some 10s of his clan members were in fairly important positions. Cen Xi, at one point, sighed and commented, "When things become extreme, they will be reversed. This is what I am fearful of." However, he did not actually resign.
By 713, it was said that Princess Taiping, Dou, Cen, Xiao Zhizhong, Cui; along with other officials Xue Ji, Li Jin (李晉) the Prince of Xinxing (a grandson of Li Deliang (李德良), a cousin of Tang's founder Emperor Gaozu), Li You (李猷), Jia Yingfu (賈膺福), Tang Jun (唐晙); the generals Chang Yuankai (常元楷), Li Ci (李慈), and Li Qin (李欽); and the monk Huifan (惠範), were plotting to overthrow Emperor Xuanzong. It was further said that they discussed, with the lady in waiting Lady Yuan to poison an aphrodisiac that Emperor Xuanzong took regularly known as chijian (赤箭, castrodia elata)). When this alleged plot was reported to Emperor Xuanzong by Wei Zhigu, Emperor Xuanzong, who had already received advice from Wang Ju (王琚), Zhang Shuo, and Cui Riyong to act first, did so. He convened a meeting with his brothers Li Fan (李範) the Prince of Qi, Li Ye (李業) the Prince of Xue, Guo Yuanzhen, along with a number of his associates — the general Wang Maozhong (王毛仲), the officials Jiang Jiao (姜皎) and Li Lingwen (李令問), his brother-in-law Wang Shouyi (王守一), the eunuch Gao Lishi, and the military officer Li Shoude (李守德) — and decided to act first. On July 29, Emperor Xuanzong had Wang Maozhong take 300 soldiers to the imperial guard camp to behead Chang and Li Ci. Then, Jia, Li You, Xiao, and Cen were arrested and executed as well. After his death, Cen's properties were confiscated.

