The monarchy of the United Kingdom is a system of government in which a hereditary monarch is the sovereign of the United Kingdom and its overseas territories. The terms British monarch and British monarchy may mean different things in different contexts beyond the United Kingdom. The present monarch is King Charles III, who has reigned since 8 September 2022. The heir apparent is his brother,. They and the Queen's husband and consort, Prince Philip, Duke of Edinburgh, undertake various public duties in accordance with their positions. Elizabeth II is Head of the Commonwealth and also reigns as head of state of 15 other Commonwealth countries. This developed from the former colonial relationship of these countries to Britain, but they are now independent and the monarchy of each is legally distinct.