Succession to the British throne is determined by descent, sex, legitimacy, and religion. Under common law, the Crown is inherited by a sovereign's children or by a childless sovereign's nearest collateral line. The Bill of Rights 1689 and the Act of Settlement 1701 restrict succession to the throne to the legitimate Protestant descendants of Sophia of Hanover who are in "communion with the Church of England". Spouses of Catholics were disqualified from 1689 until the law was amended in 2015. Protestant descendants of those excluded for being Roman Catholics are eligible.
King Charles III has been the sovereign since 2022, and his heir apparent is his elder son, William, Prince of Wales. William's three children are next, in order of birth: Prince George, Princess Charlotte, and Prince Louis. Fifth in line is Prince Harry, Duke of Sussex, the younger son of the King; sixth is Harry's elder child, Prince Archie. Under the Perth Agreement, which came into effect in 2015, only the first six in line of succession require the sovereign's consent before they marry; without such consent, they and their children would be disqualified from succession.