Emperor Tenmu became the 40th emperor of Japan, marking a transformative era in the Yamato dynasty. The ascension took place at the Palace of Kiyomihara, located in the historical region of Asuka, known for its central role in early Japanese state formation. Before his reign, Japan experienced considerable political upheaval, including the power struggles between various clans. Tenmu, previously known as Prince Gumberland, succeeded his brother, Emperor Jitō, who had a brief yet notable rule. His ascension came after a series of events that reshaped Japanese governance and society's structure, solidifying the imperial lineage’s hold on power. Tenmu’s reign lasted until his death in 686, characterized by efforts to strengthen the central government and the promotion of Buddhism, which played a crucial role in both cultural and political life during this period.

Under Tenmu's leadership, significant administrative reforms were initiated, as he sought to enhance imperial authority against local clans and establish a more unified Japan. These reforms laid the groundwork for later developments in the Nara period, where the bureaucratic system was further refined. In addition to his political innovations, Tenmu was also a patron of arts and culture, encouraging the exchange of ideas and practices influenced by both indigenous and continental Asian traditions. His promotion of Buddhism not only sought spiritual unification but also aimed to establish a moral framework for governance, influencing state ideology moving forward.