In case you ever wondered why so many members of Britain's royal family each have at least three names, it's basically to give them a choice of monikers when they take the throne.
The regnal name, it's called.
Of course, though the line of succession is long, only a select few spend any time preparing for a run as monarch. But still, none of Queen Elizabeth II's children or grandchildren have any less than three names, not including the surname Windsor or the territory attached to their title, such as Wales or Cambridge. (Even Princess Anne's kids, who don't have titles, were born Peter Mark Andrew and Zara Anne Elizabeth.)
Following the monarch's death on Sept. 8 at age 96, great-grandson Prince George, who is now second in line to the throne at 9 years old, and his siblings Princess Charlotte and Prince Louis, all have three names as well. But the further the family tree branches out—such as to spare heir Prince Harry's children Archie Harrison and Lilibet Diana, and all assorted cousins of their generation—the more likely it is that their parents only gave them first and middle names.
Which, ironically, is more like the old days. Like, the really old days.
Queen Elizabeth II's mother's name was also Elizabeth (and was later known as the Queen Mother), but the late sovereign's Roman numeral was a nod to her regnal predecessor, Queen Elizabeth I, who reigned from 1558 to 1603. And back when a parent's main concern was keeping a child alive past infancy, Elizabeth I was given just that one name at birth.
Which, all told, was easy enough for the storied royal's father, King Henry VIII, and doomed mother, Anne Boleyn, to come up with, seeing as how both of their mothers were also named Elizabeth.
Yet in the 349-year gap between their reigns, there were no other Elizabeths (in fact, there were only three queens, Mary, Anne and Victoria, amid a mess of kings), hence the just-passed monarch becoming Elizabeth II upon her ascension to the throne in 1952.
The O.G. Elizabeth's successor, King James I, was born James Charles Stuart—which sounds like several names to choose from, but Stuart was the name of the royal house of England, Scotland and Ireland at the time. Under the circumstances, James sufficed.
However, his successor, King Charles I, who was in turn followed by his son King Charles II, is where it gets tricky for the erstwhile Prince Charles, who became king the moment his mother died, and ultimately chose to reign as King Charles III.
The first Charles was executed in 1649 after being convicted of high treason for forming an alliance with Scotland, and his son spent nine years exiled in France when England became a de facto republic led by General Oliver Cromwell, who bested Charles II at the Battle of Worcester in 1651. (There's a reason why there are stacks upon stacks of thick books devoted to untangling all this.)
The monarchy was restored when Cromwell died, but Charles II's court subsequently became known for debauchery, and the king's said to have fathered at least 13 illegitimate children. Hence his being succeeded by his brother James II, rather than a descendant.
So, although his mother apparently didn't mind the history, Charles doesn't have the most illustrious of connotations on the throne. But he was born prepared: As Charles Philip Arthur George, he for all intents and purposes had three more names to choose from.
But Philip being his late father and King Arthur a legendary cuckold, there was also speculation that Charles would choose to become King George VII, history having packed six prior Georges in since 1714. (And five of them were actually named George.)
Meanwhile, James II's eldest son died young, so his daughter Mary and her husband William Henry (also known as William of Orange, his parents gave him a middle name) inherited His-and-Hers thrones, reigning as King William III and Queen Mary II (her numeric predecessor being Mary I, aka "Bloody Mary," from the 1500s).
Mary II died of smallpox at 32 and they didn't have children, so William III was succeeded by Mary's sister Anne (the quirky ailing queen portrayed by Olivia Colman in The Favourite). None of Anne's children survived her, so the crown passed to her second cousin and closest living Protestant relative—George Louis.
So he was King George I, and from then on, eponymous children of the monarchs started getting middle names, though most were content to stick with their first names.
On the crown passed to George II, and then George III (who was George II's grandson and succeeded him because his father, Prince Frederick, had died) was the first in this line to be born with three names, George William Frederick. And then George III's son and successor, George IV (born George Augustus Frederick), actually gave his daughter and sole heir a middle name.
Princess Charlotte Augusta predeceased her father, however, so George IV's younger brother, yet another William Henry, succeeded him as King William IV. (So, the current Prince William, aka William Arthur Philip Louis, who as the eldest son of the reigning monarch is now the Prince of Wales, will likely be William V.)
Then again, William IV also didn't bother to make it official with any of the ladies in his life, so his myriad children couldn't succeed him. When he died, the monarchy turned to his niece—who was the only legitimate child of William's next-youngest living brother Prince Edward.
That niece was Queen Victoria, whose 63 years and seven months on the throne was a record until Queen Elizabeth II blew past the mark in 2016 and ended up reigning for 70 years.
But in addition to inspiring the entire Victorian era, Victoria was the first queen to hand-pick her regnal name: Born Alexandrina Victoria—christened so after her godfather Tsar Alexander I of Russia—she always preferred to go by her middle name.
Victoria gave all of her nine children at least a middle name, and her eldest was christened Victoria Adelaide Mary Louisa.
The Princess Royal married herself into German royalty and out of the line of U.K. succession, so when Victoria died, her second-eldest, Albert Edward, became King Edward VII—setting his first name (which was also his father's, Victoria's incredibly adored husband Prince Albert) aside to become the first Edward on the throne in 348 years.
Edward VI's eldest, the richly named Albert Victor Christian Edward, predeceased him, so his second son George Frederick Ernest Albert became King George V.
Though he went with his given first name on the throne, perhaps George V appreciated having options, so he bestowed his eldest son with a surplus of choices: Edward Albert Christian George Andrew Patrick David.
The heir who went by David, however, only spent 50 weeks as King Edward VIII, choosing to abdicate so that he could marry twice-divorced American Wallis Simpson, after which they were the Duke and Duchess of Windsor.
And so George V's spare heir, Albert Frederick Arthur George, affectionately known around the palace as "Bertie" (as was his great-grandfather Prince Albert), stepped up as King George VI.
He's said to have picked George as his regnal name for two reasons, firstly in tribute to his father, who was very popular. But he definitely did not use his first name because Queen Victoria was so protective of her late husband's memory (she outlived him by 40 long years), that she didn't want any future Alberts in the family to outshine her prince charming. Hence her son Albert dutifully going with his middle name, Edward, when he became king.
Anyway, once King George VI ascended, that made his eldest daughter, Elizabeth Alexandra Mary, first in line to the throne. The doting father may not have expected to be the monarch himself, but he had enough foresight to give his daughter options.
Yet history has it that when Elizabeth's father died in 1952, when she was only 25, the new queen was asked what name she'd like to go by as monarch. And she replied, "My name, of course."