The Imperial House of Japan comprises those members of the extended family of the reigning Emperor of Japan who undertake official and public duties. Under the present Constitution of Japan, the emperor is the symbol of the state and unity of the people. Although he is not technically head of state, he is frequently treated as one. Other members of the imperial family perform ceremonial and social duties but have no role in the affairs of government.
The Japanese monarchy is the oldest continuous hereditary monarchy in the world still in existence. The imperial house recognizes 125 legitimate monarchs since the accession of Emperor Jimmu (traditionally dated to February 11, 660 BC), including the reigning emperor, Akihito. Most historians regard the first 14 emperors (Emperor Jimmu to Emperor Chuai) as mythical figures.
The role of the emperor of Japan has historically alternated between that of a supreme-rank cleric with largely symbolic powers and that of an actual imperial ruler. An underlying imperial cult (the idea of Arahitogami) regards the emperor as being descended from gods. Until 1945, the Japanese monarchs had always been, officially, military commanders. However, contrary to the usual role of a Western monarch, they did not practically function as such. Japanese emperors have nearly always been controlled by other political forces, to varying degrees