==Early life and reign== The Chūzan Seikan (1650), the first official history of the Ryūkyūan Kingdom, and Chūzan Seifu (1701) state that Shunten was the son of Minamoto no Tametomo (1139 – 1170). Tametomo was exiled to a penal colony on Izu Ōshima following his defeat in the Hōgen Rebellion of 1156. According to this theory, Tametomo then...