After considering there was a record that Tsunemoto showed his existence only for seven or eight years in the history although he was the originator of Seiwa-Genji (Minamoto clan), his correct birth and death year was unknown.
清和源氏の祖でありながら歴史の表舞台に登場したのが僅か7、8年に過ぎない事もあって正確な生没年は未詳である。