The Commonwealth of Nations, commonly known as the Commonwealth, is an intergovernmental organisation of 53 member states that were mostly territories of the former British Empire. The Commonwealth operates by intergovernmental consensus of the member states, organised through the Commonwealth Secretariat, and non-governmental organisations, organised through the Commonwealth Foundation. The Commonwealth dates back to the mid 20th century with the decolonisation of the British Empire through increased self-governance of its territories. It was formally constituted by the London Declaration in 1949, which established the member states as "free and equal". The symbol of this free association is Queen Elizabeth II who is the Head of the Commonwealth. The Queen is also the monarch of 16 members of the Commonwealth, known as Commonwealth realms. The other members of the Commonwealth have different persons as head of state: 32 members are republics and five members are monarchies with a different monarch. Member states have no legal obligation to one another. Instead, they are united by language, history, culture, and their shared values of democracy, human rights, and the rule of law.