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 of Japan
There are two Japanese words equivalent to the English word "Emperor": "tennō" (, "heavenly sovereign"), which is used exclusively to refer to the Emperor of Japan, and "kōtei" (皇帝, the title used for all other foreign Emperors), which is used primarily to describe non-Japanese Emperors. "Sumeramikoto" ("the Imperial person") was also used in Old Japanese. The term "tennō" was used by the Emperors up until the Middle Ages; then, following a period of disuse, it was used again from the 19th century. In English, the term "mikado" ( or ), literally meaning "the honorable gate" (i.e. the gate of the imperial palace, which indicates the person who lives in and possesses the palace), was once used (as in "The Mikado", a 19th-century operetta), but this term is now obsolete. (Compare Sublime Porte, an old term for the Ottoman government.)