《宋史·列传·卷二百三十一》
蔡京天资凶狠狡诈，舞弄权术，以智慧控制别人，在皇帝面前，专门窥伺人主之意以求固位专宠，始终对皇帝说，不必拘泥流俗，应该竭尽四海九州的财力来满足自己享乐。
京天资凶谲，舞智御人，在人主前，颛狙伺为固位计，始终一说，谓当越拘挛之俗，竭四海九州之力以自奉。
Cai Jing was vicious and cunning by nature, and he was good at playing tricks. He would use his intelligence to control others. In front of the Emperor, he would try to guess the Emperor’s thoughts so that he could maintain his position and enjoy his favor. He always told the Emperor that the flow of the common should not be followed, and that he should use all of the wealth of the world to meet his demands.