Empress Kōken
Empress Kōken first reigned from 749 to 758, then, following the Fujiwara no Nakamaro Rebellion, she reascended the throne as Empress Shōtoku from 765 until her death in 770. Empress Kōken was involved in an affair with priest Dōkyō and appointed him Grand Minister in 764. In 766, he was promoted to Hōō (priestly emperor) and in 770 had tried to ascend the throne by himself. The death of the Empress and resistance from the aristocracy destroyed his plans. This incident was a reason for the later move of the Japanese capital from Nara (Heijō).