Queen Elizabeth II was the first child of the Duke and Duchess of York. After the the abdication of his brother in 1936, the Duke became King George VI.
In 1947 Elizabeth married Philip, Duke of Edinburgh, with whom she has four children: Charles, Prince of Wales; Anne, Princess Royal; Prince Andrew, Duke of York; and Prince Edward, Earl of Wessex.
When her father King George VI died in February 1952, Elizabeth became head of the Commonwealth and queen regnant of the independent Commonwealth countries: United Kingdom, Canada, Australia, New Zealand, South Africa, Pakistan, and Ceylon.
Source: Wikipedia