The Imperial House is the reigning dynasty of Japan, consisting of 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 of the unity of the people". Other members of the imperial family perform ceremonial and social duties, but have no role in the affairs of government. The duties as an emperor are passed down the line to their male children. The Japanese monarchy is the oldest continuous hereditary monarchy in the world.