However, the Emperor was in poor health when he became the Crown Pprince and had a sensitive relationship with his father the Emperor at that time; according to "Nihon Koki," there was a rumor that the crown prince was involved in the incident of Togu-bo Tachihaki (no) Toneri being killed in 793, or that in 805 the Emperor, who was in serious medical condition, recovered temporarily and ordered the Crown Pprince to go to the Imperial Palace, but when he refused to do so, FUJIWARA no Otsugu reprimanded him and he finally went to the Imperial Palace for a while.
だが、病弱であった上に父天皇との関係も微妙であり、『日本後紀』によれば、延暦12年（793年）に春宮坊帯刀舎人が殺害された事件の背景に皇太子がいたと噂された事や、同24年（805年）に一時重態であった天皇が一時的に回復したために皇太子に対してに参内を命じたのにも関わらず参内せず、藤原緒嗣に催促されて漸く参内したことなどが記されている。