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 Go-Saga
Emperor Go-Saga (後嵯峨天皇 "Go-Saga-tennō") (April 1, 1220 – March 17, 1272) was the 88th emperor of Japan, according to the traditional order of succession. This reign spanned the years 1242 through 1246.