《资治通鉴·唐纪·唐纪六十五》
起初，唐宣宗想让于琮娶永福公主，后又将婚事搁置下来，宰相问其中缘故，唐宣宗说： 朕近日与这个女儿在一起吃饭，当朕的面她就把筷子折断。
初，上欲以悰尚永福公主，既而中寝。宰相请其故，上曰： 朕近与此女子会食，对朕辄折匕箸。
At first, Tang Xuanzong wanted Yu Cong to marry Princess Yongfu, but later put the marriage on hold. The prime minister asked why, and Tang Xuanzong said: I have been eating with this daughter recently, and she broke her chopsticks in front of me.