After Takauji ASHIKAGA received an inzen (a decree issued by a retired Emperor) from Emperor Kogen of the Jimyoin line, a rival to Emperor Godaigo's line, he established the Northern Court (Japan) and was appointed Seii taishogun; thus, the head family of the Ashikaga clan became the Ashikaga Shogunate family.
足利尊氏が後醍醐天皇の皇統とは宿敵にあたる持明院統の光厳天皇の院宣を受けて、北朝(日本)を樹立、征夷大将軍に任ぜられることで足利宗家は足利将軍家として成立することとなった。