In 672, Prince Oama (later Emperor Tenmu) fled to the mountains of Yoshino as a Buddhist monk, raised an army from virtually nothing, and within a month defeated his nephew Prince Otomo in the Jinshin War — ancient Japan’s greatest civil conflict. As emperor he formalized the title ‘tenno’ (emperor), promoted the ritsuryo legal code, and ordered the compilation of the Kojiki and Nihonshoki.