British princess
The use of the title of Princess of the United Kingdom of Great Britain and Northern Ireland is entirely at the will of the sovereign, and is now expressed in letters patent. Individuals holding the title of princess are styled "Her Royal Highness" (HRH). The current letters patent were issued in 1917 during the First World War, with one extension in 2012.
On 18 April 1917, pursuant to the then custom of the royal family, Frederica of Hanover was styled among other titles, a British princess, from birth. She was also the newest granddaughter and subject of Wilhelm II, German Emperor, while Germany and Britain were fighting against each other in the war. George V issued letters patent on 30 November 1917, to restrict the automatic assignment of the title "princess" and the use of the style "Royal Highness" to the following persons:
- the legitimate daughters of a British sovereign,
- the legitimate male line granddaughters of a British sovereign,
- the lawful wife of a British prince.
On 31 December 2012, Queen Elizabeth II issued letters patent enabling daughters of the eldest son of the Prince of Wales to enjoy the princely title (princess) and style of Royal Highness, as opposed to only the eldest son (the 1917 patent having extended "prince" to his eldest living son).