The union of the United Kingdom and Hanover began with the proclamation of King of the United Kingdom George III in 1814. Subsequently, King George IV and King William IV went on to have the same title. In 1837, after the demise of King William IV, different laws prevented from taking over the throne with the same title. In Hanover, the Salic law prevailed thereby succession to or through a female was not allowed. This rule wasn’t applicable in Great Britain, hence Queen Victoria, niece of William IV became the queen whereas Ernest Augustus (brother of William IV) became the King of Hanover.