《旧唐书·列传·卷十三》
太宗曾问萧瑀： 我想让子孙长久继承帝位，天下永远安宁，究竟该怎样办呢？ 
太宗常谓瑀曰： 朕欲使子孙长久，社稷永安，其理如何？ 
Emperor Taizong once asked Xiao Yu, "I want my descendants to inherit the throne for a long time, and for the world to be peaceful forever. What should I do?"