With copper as a mirror, we can dress our clothes, and with history as a mirror, we can know the rise and fall.

It means: using copper as a mirror can tidy up a person's clothes; Take others as a mirror, you can know your own gains and losses; Taking history as a mirror, we can know the ups and downs of history.

This sentence is from Li Shimin, and the source is the Biography of Wei Zhi in the Old Tang Dynasty: In the seventeenth year of Tang Zhenguan (AD 643), Wei Zhi, who dared to speak, died of illness. Emperor Taizong was very sad. He said with tears: "husband, with copper as a mirror, you can dress well;" Taking history as a mirror, we can know the rise and fall; Take people as a mirror, you can know the gains and losses. Wei Zhi didn't! I lost a mirror! "

It means: a person can see whether his clothes and hats are properly dressed by looking at copper as a mirror; Looking at people as a mirror, you can find your own right and wrong; Taking history as a mirror, we can know the reasons for the rise and fall of a country. After Kevin·Z died, I lost a good mirror.

Extended data

In the 13th year of Daye (6 17), Wei Zhi became an official under the account of Cheng Yuanbao in Wuyang County. Yuanbao got up and responded to Shi Biao, sending out tiles. All the letters from Yuanbao to Shi Mi were written by Kevin·Z. Seeing that Wei Zhi was very literary, Shi Biao summoned Wei Zhi and Wei Zhi and put forward ten measures to strengthen the tile, but Shi Biao didn't have to.

In the 14th year of Daye (6 18), Wang attacked Cang City and was defeated by Shi Mi. Wang turned to attack Luokou and was defeated by Smith again. Wei Zhi said to Zheng Xiangchang: "Although Shi Biao won many victories, many soldiers were killed and wounded, and there was no treasure house in Wagang Mountain, so the soldiers did not have meritorious service. It is better to go deep into the ditch, occupy the danger, hold a stalemate with the enemy, wait for the enemy to run out of food, and lead the army to pursue. This is the way to win.

If Luoyang had no food, Wang would have fought a decisive battle with our army, but we didn't fight him at this time. "Zheng Xiang dismissed Wei Zhi's words, saying it was a cliche. Wei Zhi said, "This is a clever plan. How can it be a cliche? "Leave at a stroke.