《北史·列传·卷五十九》
开皇二十年，文帝车驾自仁寿宫御临大兴殿，对侍臣说： 我刚回到京师，理应开怀欢乐，可是不知怎么了，反而愁苦不乐。 
开皇二十年，车驾至自仁寿宫，御大兴殿，谓侍臣曰： 我新还京师，应开怀欢乐，不知何意，翻悒然愁苦。 
In the 20th year of Emperor Wen’s reign, the emperor traveled from Renshou Palace to Daxing Hall and said to his courtiers, “I have just returned to the capital, and I should be happy, but for unknown reasons, I feel distressed and unhappy instead.”