《旧唐书·列传·卷一百零六》
元和十三年，于頔上表请求辞官归家，宰臣拟授他太子少保，皇上御笔改为太子宾客。
十三年，頔表求致仕。宰臣拟授太子少保，御笔改为太子宾客。
In the 13th year of the Yuanhe period, Yu Di submitted a memorial to request for resignation from his post and to return home. The prime minister planned to grant him the title of crown prince's overseer of discipline, but the emperor changed it with his imperial brushwork to crown prince's guest.