Historic legislation has been announced by David Cameron to ensure gender equality in claims to the throne.
For the first time in British history, a princess will be just as likely to be queen, as a prince to be king, with equal rights for sons and daughters of monarchs.
The UK has had only a handful of female monarchs of varying success - from the disastrous Matilda in the 12th century to the much-loved Elizabeth I in the 16th.
British queens have had mixed fortunes, but which did we miss out on, and how might the country have been different under the latest law?
Under the new legislation, Margaret Tudor would have succeeded Henry VII in 1509. Instead she lost out to her younger brother, Henry VIII. And without Henry VIII's marital issues, it is very unlikely that we would ever have broken with Rome, as we did in 1533.
Elizabeth Stuart, the Winter Queen of Bohemia, would have succeeded her father James I in 1625. We would never have had Charles I. Controversy rages among historians as to whether he caused the English Civil War, but with Queen Elizabeth it arguably could have been avoided.
Queen Victoria's daughter, Princess Victoria, would have succeeded in January 1901, rather than Edward VII. She would have died less than seven months later, handing the throne to Kaiser Wilhelm II. Britain would have been ruled by the German emperor during the First World War.