TAIRA no Masamori was from the Sadamori branch of the Kanmu-Taira clan and his father, Masahira, was not such a powerful member among the warrior aristocracy, but donated his property in Iga Province in 1097 to the Rokujyo-in Temple (Retired Emperor Shirakawa's daughter, Ikuhomonin no Mido) and established Tomoda no sho.
平正盛は、桓武平氏貞盛流の伊勢平氏に出自し、その父の正衡までは軍事貴族の中でもそれほど有力な一族ではなかったが、永長2年（1097年）伊賀国の所領を六条院（白河上皇の娘・郁芳門院の御堂）に寄進して鞆田荘を成立させた。