Records of heads of state
Officially, the current Emperor of Japan, Akihito is the 125th in line from the first emperor Jimmu, who is variously believed to have reigned in the 1st or 7th century BC. The earliest documentary evidence is only for the 29th emperor, Kinmei (AD 509–571); however, this is sufficient such that even the most conservative of estimates still places the Japanese imperial family as among the oldest lines in the world today.
Emperor of Japan
Outside Japan, the previous Emperor is usually called Hirohito in English, although he was never referred to as Hirohito in Japan, and was renamed "Shōwa Tennō" after his death, which is the only name that Japanese speakers currently use when referring to him.