By
魏征 (Tang dynasty, 637 CE), presented to Emperor
唐太宗 (Li Shimin) during the Zhenguan era. The essay lays out ten things a ruler must reflect on (
十思), including 'when you see something desirable, think of contentment' and 'when you fear arrogance, think of the humility of rivers and seas.' Wei Zheng became the archetype of the honest remonstrating minister; Taizong later said, 'With bronze as a mirror one can straighten one's clothes; with history as a mirror one can see rise and fall; with a man as a mirror one can know gain and loss' - referring to Wei Zheng's death.