The Asuka Era -- Japan

When emperor Tenji died in 671, he had two apparent successors. One is his elder son, prince Otomo . The other is his elder brother, prince Oama. Tenji had named prince Otomo as his successor two years before. So prince Oama had retired from the government and become a Buddhism priest. If he had remained in government, he would have been killed by some supporter of prince Otomo. So he had escaped to a temple in the Yoshino mountains.
But when emperor Tenji died, the two princes broke a battle for the throne. Finally prince Oama won, and prince Otomo comitted suicide. Prince Oama became the new emperor Tenmu. This war is called "the Jinshin War."