In 1577, Masamune celebrated his coming of age, and in 1579, he got married with Aihime whose father was a warlord of Sendo and the lord of the Miharu-jo Castle, Kiyoaki TAMURA.
天正5年（1577年）に元服、天正7年（1579年）には仙道の戦国大名で三春城主田村清顕の娘愛姫を正室とする。