Emperor of Japan
Currently, the Emperor of Japan is the only head of state in the world with the English title of "Emperor". The Imperial House of Japan is the oldest continuing monarchical house in the world. The historical origins of the Emperors lie in the late Kofun period of the 3rd–7th centuries AD, but according to the traditional account of the "Kojiki" (finished 712) and "Nihon Shoki" (finished 720), Japan was founded in 660 BC by Emperor Jimmu, who was said to be a direct descendant of the sun-goddess Amaterasu. The current Emperor is Akihito. He acceded to the Chrysanthemum Throne upon the death of his father, Emperor Shōwa (Hirohito), in 1989. The Japanese government announced in December 2017 that Akihito will abdicate on 30 April 2019.
Emperor Go-Daigo
Emperor Go-Daigo (後醍醐天皇 "Go-Daigo-tennō") (November 26, 1288 – September 19, 1339) was the 96th emperor of Japan, according to the traditional order of succession. He successfully overthrew the Kamakura shogunate in 1333 and established the short lived Kenmu Restoration to bring the Imperial House back into power. This was to be the last time the emperor had any power until the Meiji Restoration in 1868. The Kenmu restoration was in turn overthrown by Ashikaga Takauji in 1336, ushering in the Ashikaga shogunate, and split the imperial family into two opposing factions between the Ashikaga backed Northern Court situated in Kyoto and the Southern Court based in Yoshino led by Go-Daigo and his later successors.