진군
In late 220, some months after Cao Cao's death, Cao Pi (Cao Cao's son and successor) forced Emperor Xian to abdicate in his favour and established the state of Cao Wei to replace the Han dynasty, with himself as the new emperor. He enfeoffed Chen Qun as the Marquis of Changwu Village and appointed him as a Master of Writing in the government. Chen Qun proposed the nine-rank system for civil service nominations and it became enshrined in the laws of the Cao Wei state.