Wei Zheng served Emperor Taizong of Tang as a remonstrance official and at times angered him. In 632, back from court, the emperor raged: “I must kill that country bumpkin.” Empress Zhangsun calmed him.
When Wei Zheng died in 643, Taizong said: “With bronze as a mirror, one can straighten one’s clothes. With the past as a mirror, one can know rise and fall. With a person as a mirror, one can see right and wrong. Now Wei Zheng is gone, and I have lost a mirror.”
Remonstrance of this kind depended on a ruler willing to listen.