How old is Japan’s imperial monarchy?

Japan’s imperial monarchy is generally regarded as the world’s oldest surviving monarchy. Traditional Japanese histories trace the imperial line to Jimmu, who is said to have become Japan’s first emperor in 660 bce and to have descended from the sun goddess Amaterasu. The earliest emperors, however, cannot be historically verified. The historical imperial institution developed from the rulers of the Yamato polity and took a more recognizable form under Chinese influence during the 7th and 8th centuries ce.