In the record of "Zaikyu-ki of Jisha-machi, Kasa County, Tango Province," there was a description that Shichiroemon Sukekage SHIMOJIMA, the 29th descendant of the Emperor Koko, the lord of the Hebishima Castle came to this province from Shima no sho, Ikaruga County, Tanba Province, but when he came remained unknown.
丹後国加佐郡寺社町在旧起においては「蛇島城主光孝天皇二十九代末孫下志万七郎右衛門助景丹波国何鹿郡志万庄より当国に来る時代不知。」という記述もある。