The son and successor of Harumune, a successful kokujin lord, Terumune was officially named the 16th head of the Date clan by Shogun Ashikaga Yoshiteru, who awarded him the character 'Teru' in his name. Ascending to his position at the age of 17, Terumune expanded from Yonezawa-jo to rule over 30 districts. In 1584, Terumune retired in favor of his eldest son Masamune. Masamune continued the war with the Date's perennial enemy, the Hatakeyama, prompting Hatakeyama Yoshitsugu to call on Terumune to intercede. Yet, rather then talk peace when they met, Terumune was kidnapped by Yoshitsugu at what was to have been a social meeting. Masamune, learning of the news, gave pursuit and managed to overtake the Hatakeyama and their hostage. In the course of the confrontation that ensued, Terumune called out to his son to forget about his (Terumune's) safety and to open fire with the arqeubuses he had on hand. Terumune drew his own sword and in the melee was cut down. This transpired on 29 November 1585. Terumune had been known for his gentle disposition and was well-loved by many Date retainers, some of whom elected to commit suicide and follow him in death. He had been married to a daughter of Mogami Yoshimori of Dewa province.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005