Elizabeth II (Elizabeth Alexandra Mary; born 21 April 1926) is the queen regnant of sixteen independent sovereign states known informally as the Commonwealth realms: the United Kingdom, Canada, Australia, New Zealand, Jamaica, Barbados, the Bahamas, Grenada, Papua New Guinea, the Solomon Islands, Tuvalu, Saint Lucia, Saint Vincent and the Grenadines, Belize, Antigua and Barbuda, and Saint Kitts and Nevis. She holds each crown separately and equally in a shared monarchy, as well as acting as Head of the Commonwealth, Supreme Governor of the Church of England, Duke of Normandy, Lord of Man, and Paramount Chief of Fiji. As a constitutional monarch, she is politically neutral and by convention her role is largely ceremonial.

When Elizabeth was born, the British Empire was a pre-eminent world power, but its influence declined, particularly after World War II, and the empire evolved into the modern Commonwealth of Nations. Her father, George VI, was the last Emperor of India. On his death in 1952, Elizabeth became Head of the Commonwealth, and queen of seven independent Commonwealth countries: the United Kingdom, Canada, Australia, New Zealand, South Africa, Pakistan, and Ceylon. During her reign, which at 57 years is one of the longest for a British monarch, she became queen of 25 other countries within the Commonwealth as they gained independence from Britain. She has been the sovereign of 32 individual nations, but half of them later became republics.

Elizabeth married Prince Philip, Duke of Edinburgh, in 1947. The couple have four children and eight grandchildren.