 The title of Emperor was borrowed from China, being derived from Chinese characters and was retroactively applied to the legendary Japanese rulers who reigned before the 7th–8th centuries AD.According to the traditional account of the Nihon Shoki, Japan was founded by Emperor Jimmu in 660 BC.Modern historians generally believe that the Emperors till Suinin are 'largely legendary' as there is insufficient material available for verification and study regarding their lives.