Ping Dang 平當, courtesy name Ping Zisi 平子思, was a high official of the late Former Han period. He came from Pingling 平陵 (near modern Xianyang 咸陽, Shaanxi) and was a appointed professor boshi 博士erudite because of his proficiency in the Confucian Classics. Ping Dang adhered to the school of Confucians that interpreted natural calamities as expressions of Heaven towards the performance of a ruler. He also studied the chapter Yugong禹貢The Tribute of Yu that describes the various provinces of China, their rivers, quality of soil and local products applicable for tribute to the court. Emperor Cheng therefore appointed him juduwei 騎都尉 and ordered him to investigate dams and dykes of the empire. When Emperor Ai succeeded to the throne, Ping Dang was promoted to guanglu dafu 光祿大夫 and later to Censor-in-chief御史大夫 and Counsellor-in-chief 丞相. For that position he was enfeoffed as Marquis within the passes guanneihou 關內侯. Just at that time he became seriously ill and planned to decline the imperial order of promotion, yet his relatives forced him to at least accept the enfeoffment and the inheritable title. Ping Ding, as a man of honour, refused the request of his relatives and declined to accept the official seals, yet the emperor forced him to accept. Ping Dang died shortly after. Source: Cang Xiuliang 倉修良 (1996). Hanshu cidian 漢書辭典, p. 178. Jinan: Shandong jiaoyu chubanshe.