In the early Heian period, the Tomo clan, like the Ki clan, was considered to be the clan that carried the ancient practices of warriors, but as the samurai gained power, the Tomo clan's political influence faded, and after TOMO no Tadakuni became the first Shinto priest of Tsurugaoka Hachiman-gu Shrine, the bloodline was inherited, as the job was passed on through generations.
平安時代前期には、紀氏と並んで武人の故実を伝える家とされたが、武士の台頭とともに伴氏は歴史の表舞台から姿を消していく事となり、その後は伴忠国が鶴岡八幡宮初代神主となって以降、その社職を継承しながら血筋を伝えていく事となる。