However, these works were based purely on previous myths and were made six centuries after the alleged events probably because of the political circumstances after the Satsuma Invasion – although still independent until the 19th century, was subordinate to the Satsuma Domain and thus intermediary to the Tokugawa shogunate. The story is inspired by political interests to connect and legitimize the relation of Japan's imperial family with Ryūkyū. In the 12th century, somekind of migration or association from the mainland Japan with the Okinawan chieftains probably happened, but as the historical and archeological-traditional evidence indicate men from the defeated Taira clan who fled Minamoto's clan vengeance, at the time of mythological-historical writing in 17th century, was mentioned Tametomo who was from the same Minamoto clan as the Tokugawa's "shōguns".