Since the almost 30-year-old shogun Yoshimasa had no heir by 1464, he adopted his younger brother Ashikaga Yoshimi in order to succeed him. However, Yoshihisa was born in the next year starting a struggle for succession between brothers that erupted into the Ōnin War starting in 1467, beginning the Sengoku period of Japanese history. In the middle of hostilities, Yoshimasa retired in 1473, relinquishing the position of Seii Taishogun to Yoshihisa.