This is what Tang Taizong said after the death of Wei Zheng, the remonstrating minister, in the 17th year of Zhenguan in the Tang Dynasty. The original sentence is: "Husband, use copper as a mirror to straighten your clothes; use ancient times as a mirror to know Ups and downs; use people as mirrors to know gains and losses. If Wei Zheng is gone, I will be dead as a mirror!"?

The main idea is: "A person can use copper as a mirror to see whether he is dressed properly. "Using history as a mirror, you can understand the reasons for the rise and fall of a country; using people as a mirror, you can discover your own rights and wrongs." Once Wei Zheng died, I lost a good mirror."

This shows that Wei Zheng was in the Tang Dynasty. It played an important role during Taizong's reign.

This sentence still serves as a warning to us today, reminding us that we should always use others as examples to face our own mistakes and correct them.