《北史·列传·卷二十》
十五岁时，周文帝见到他以后很惊讶，就让他和皇家子弟一起读书，隋文帝也在其中。
年十五，周文帝见而异之，令与诸子同就学。隋文帝亦在其中。
When he was fifteen years old, Emperor Zhou Wen was surprised to see him, and asked him to study with the children of the royal family, including Emperor Sui Wen.