The Constitution of the Soviet Union recognised the Presidium of the Supreme Soviet and the earlier Central Executive Committee (CEC) of the Congress of Soviets as the highest organs of state authority in the Union of Soviet Socialist Republics (USSR) between legislative sessions. Under the 1924, 1936 and 1977 Soviet Constitutions these bodies served as the collective head of state of the Soviet Union. The chairman of these bodies personally performed the largely ceremonial functions assigned to a single head of state but was provided little real power by the constitution.