旧唐书

Compiled under the Later Jin, 后晋, one of the Five Dynasties, and presented in 945 by the chief minister 刘昫, in 200 scrolls. It was simply 唐书 until the Song produced 新唐书 in 1060, and has been the old one ever since. Because it follows Tang court records closely, historians value it for its original documents. It is the sixteenth of the 二十四史.

Its biography of the outspoken minister 魏征 records what Emperor 唐太宗 said at his death: with bronze as a mirror you can straighten your clothes, with history as a mirror you can see why states rise and fall, and with people as a mirror you can see your own mistakes. Losing Wei Zheng, he said, he had lost a mirror.