Pei Yan
At some point, Pei Yan passed the imperial examination, and he was made the food storage officer at Pu Prefecture (濮州, roughly modern Heze, Shandong). He eventually served successively as assistant imperial censor, imperial archivist, deputy minister of defense, and eventually "Huangmen Shilang" (黃門侍郎): deputy head of the examination bureau of government (門下省, "Menxia Sheng"). In 680, he was given the designation of "Tong Zhongshu Menxia Sanpin" (同中書門下三品), making him a chancellor "de facto". Later that year, when Emperor Gaozong's crown prince Li Xian was accused of treason, Emperor Gaozong had him, Xue Yuanchao, and Gao Zhizhou investigate. Eventually, Li Xián was deposed and replaced by his brother Li Zhe.