Since the 18th century, the head of the Al Khalifa, the country's ruling family, has assumed the title of Amir. A constitution promulgated  in 2002 established Bahrain as a constitutional hereditary monarchy whose head of state is now titled king. Under the new constitution the executive is composed of a prime minister, who is head of the government, and a Council of Ministers, all of whom are appointed by the king. The legislative branch consists of two houses: a 40-member Consultative Council  that is also appointed by the king and a 40-member Chamber of Deputies  that is elected by universal adult suffrage.