Known since childhood as a person of genius, Imperial Prince Kazurawara, who was also a founder of the Taira clan, celebrated his coming of age along with Prince Otomo (later Emperor Junna), a half-brother by the same father, in 789.
平氏の祖で、幼少から俊秀として知られており、798年（延暦17年）、異母兄弟の大伴皇子（後の淳和天皇）と共に元服。