Charlotte became the first female royal to benefit from The Succession to the Crown Act (2013), which states that girls will not be overtaken by younger brothers.
While Charlotte has retained her place as third-in-line to the throne in front of Louis, other female royals missed out on the change, as the Act only applies to those born after 28 October 2011.
The late Queen and Duke of Edinburgh’s only daughter Princess Anne is much further down the line of succession than her younger brothers Prince Andrew and Prince Edward.
The Princess Royal, who celebrated her 72nd birthday in August, is currently in 16th place behind her niece Lady Louise Windsor.
The Earl and Countess of Wessex’s daughter Lady Louise Windsor, 19, was also overtaken by her younger brother James, Viscount Severn in the line of succession after his birth in 2007. James is currently 14th in line, while Lady Louise is 15th.
Princess Charlotte is the only female royal who has benefited from this change so far.