The intricacies of Royal names and titles
In the modern British royal family, nomenclature is rarely straightforward. Unlike most families where a surname is simply passed down from father to child, the House of Windsor operates under a dense framework of Letters Patent, historic Privy Council declarations, royal houses, and peerage titles. For a child born across the Atlantic to parents who have stepped back from frontline working royal duties, the question of a surname involves a blend of statutory heritage, personal choice, and centuries-old tradition.
This comprehensive first part of our expert analysis explores the historical foundations, legal documents, and official choices that define the surname of Princess Lilibet.
The historical blueprint: The origins of Mountbatten-Windsor
To understand Princess Lilibet's last name, one must first travel back through the legal architecture established by the British monarchy in the 20th century. Historically, members of the British royal family belonged to a dynastic house and did not routinely use a functional surname. Instead, they were known simply by their Christian names and their territorial designations or house names (such as the House of Stuart or the House of Windsor, which was adopted by King George V in 1917 amidst anti-German sentiment during the First World War).
However, the landscape shifted significantly in 1960. Queen Elizabeth II and her husband, Prince Philip, Duke of Edinburgh, wished to distinguish their own direct descendants from the broader royal house. Consequently, an Order-in-Council was declared stating that descendants of the Queen—other than those enjoying the style of Royal Highness and the title of Prince or Princess, or female descendants who marry—would carry the hyphenated surname Mountbatten-Windsor.
This surname beautifully bridged two historic lineages:
Windsor: Representing the royal house of Queen Elizabeth II.
Mountbatten: Representing the anglicized surname adopted by Prince Philip’s maternal family (originating from the Battenberg family).
Thus, Mountbatten-Windsor became the official personal surname utilized by members of the royal family when a surname is legally or practically required, distinguishing them on birth certificates, passports, and legal registries.
Birth certificates and official records: Lilibet Diana Mountbatten-Windsor
When Princess Lilibet was born in California in 2021, her birth was officially registered under the full name Lilibet Diana Mountbatten-Windsor.
The inclusion of "Mountbatten-Windsor" as her legal surname aligns with the precedent set by her older brother, Prince Archie (born Archie Harrison Mountbatten-Windsor). Even though Prince Harry and Meghan Markle stepped down as working members of the royal family in early 2020 and relocated to Montecito, California, they chose to maintain the historic hyphenated family name for their children.
From a strict legal and documentary perspective, her birth certificate establishes her family identifier as Mountbatten-Windsor. This connects her directly to her great-grandparents, Queen Elizabeth II and Prince Philip, preserving the dynastic bridge intended by the 1960 decree.
The shift to "Sussex": Dynastic changes and modern usage
While "Mountbatten-Windsor" remains etched on formal documents, the nuances of royal naming conventions allow for alternative social and titular identifiers. Following the accession of King Charles III to the throne in September 2022, the status of Harry and Meghan's children changed. As grandchildren of the reigning monarch, Archie and Lilibet automatically became entitled to use the royal titles of Prince and Princess, alongside the style of Royal Highness, under the 1917 Letters Patent issued by King George V.
After months of public discussion, the Duke and Duchess of Sussex formally utilized these titles in March 2023, announcing Lilibet’s christening under the style of Princess Lilibet of Sussex.
In royal tradition, princes and princesses holding territorial designations often use their parent’s peerage title as a functional surname or descriptor in everyday life, much like how Prince William and Kate Middleton's children historically used "Cambridge" (and later "Wales") instead of Mountbatten-Windsor in school settings. Consequently, reports and family updates indicated that the Sussex family adopted Sussex as a primary everyday surname-style for their household, reflecting their ducal title.
...Furthermore, the naming conventions of the British royal family have long fascinated genealogists, historians, and royal watchers alike. When Prince Harry and Meghan Markle welcomed their daughter on June 4, 2021, at Santa Barbara Cottage Hospital in California, they chose the historic name Lilibet Diana Mountbatten-Windsor.
The moniker carried deep familial significance: "Lilibet" was the intimate family childhood nickname of Queen Elizabeth II, while "Diana" honored Harry’s late mother, Diana, Princess of Wales. However, beyond her first and middle names, her official surname and style have evolved in tandem with her place in the line of succession and the decisions made by her parents regarding royal titles.
The dual identity: Mountbatten-Windsor versus Sussex
To fully understand Princess Lilibet’s surname, it is essential to distinguish between her legal family surname and the dynastic surname utilized by members of the British monarchy:
Mountbatten-Windsor: Established by an Order in Council in 1960, this hyphenated surname applies to the male-line descendants of Queen Elizabeth II and Prince Philip. While senior working royals often drop a surname entirely in favor of their peerage titles (such as Wales), non-working descendants or those requiring a standard legal surname utilize Mountbatten-Windsor. At birth, Lilibet was legally registered with this surname.
Sussex: Following the coronation of King Charles III, Prince Harry and Meghan's children became officially entitled to use the prince and princess titles. In line with established royal protocol, where children take the territorial designation of their parents' peerage as a surname (similarly to how Princes William and Harry grew up using Wales after their father's title, the Prince of Wales), the family updated their official records and platforms to reflect Sussex as the children's working surname.
Cultural and global context
As the first direct royal-line princess born in the United States, Lilibet's naming conventions bridged two distinct legal and cultural worlds. In the United States, birth certificates record standard first, middle, and last names rigidly, making Mountbatten-Windsor her official birth surname on American documentation. Meanwhile, within the institutional framework of the British monarchy, her designation as Princess Lilibet of Sussex reflects her membership in the House of Windsor and her status as a granddaughter of the reigning monarch.
Whether referenced by her birth surname of Mountbatten-Windsor or her titular surname of Sussex, Princess Lilibet’s name serves as a permanent bridge connecting her American upbringing with centuries of British royal history.