With copper as a mirror, you can be well dressed; Taking history as a mirror, we can know the rise and fall; Looking at people as a mirror, we can see the gains and losses.

Wei Zhi Biography of Old Tang Dynasty Emperor Taizong Li Shimin: Husband can dress with copper as a mirror; Taking history as a mirror, we can know the rise and fall; Looking at people as a mirror, we can see the gains and losses. I have kept these three mirrors in case I pass by. Now that Wei Zhi is dead, so is a mirror!