In 498 B.C.（the 12th year of Dinggong，Duke of the state of Lu），Confucius was in the state of Lu as Minister of Justice.In order to weaken the influence of the ministers and strengthen the power of the state，Confucius made a suggestion to Dinggong to dismantle the three castles built by the relatives of the ministers.He met strong opposition from Gongjian Chufu of the Mengsun family.He had to give up the idea.