Before Prince William and Kate’s wedding, the Cartier Halo Tiara had not been seen in public for some years.
On her wedding day, the Princess of Wales donned a tiara for the first time ever, but the Princess Royal and the late Princess Margaret both wore it first.
The Carter Halo tiara belonged to the late Queen Elizabeth II, who gave it to Kate for her wedding to William in 2011.
In 1936, her father, King George VI, gave Cartier the initial order to create the tiara for his wife, the Queen Mother.
The diadem, which has 149 baton diamonds and 739 brilliant diamonds, was given to then-Princess Elizabeth on her 18th birthday, although the late Queen was never seen wearing it in public.
Instead, Princess Margaret, her younger sister, started wearing it frequently.
Princess Margaret, Countess of Snowdon was the youngest child of the late King George VI and the Queen Mother.
She and her older sister, Elizabeth, were educated at home by their governess, Marion Crawford, while they grew up in Windsor.
Margaret, who would have turned 93 on Monday, first wore the Cartier Halo Tiara at the festivities honouring Queen Juliana of the Netherlands’ Coronation in 1948.
Throughout the 1940s and 1950s, she wore the tiara repeatedly, most memorably at Queen Elizabeth II’s 1953 Coronation.
After marrying Antony Armstrong-Jones in 1960, Princess Margaret decided to don her wedding tiara (known as the Poltimore tiara) more frequently as opposed to the Cartier Halo Tiara.
Princess Margaret was not the only royal to wear the Cartier Halo Tiara before Kate’s wedding in 2011.
It was the same Cartier Halo Tiara that Princess Anne wore for her tiara debut at the state inauguration of Parliament in 1967 when she was 17 years old.
In the 1960s and 1970s, she routinely wore the diadem to evening events like ballroom dancing and charity dinners.
Prior to Kate’s marriage to William, the Cartier Halo Tiara vanished from sight for a while. The Princess of Wales has only ever worn her wedding tiara at her royal nuptials in 2011.
Since that time, she has been loaned the Lover’s Knot and Lotus Flower tiaras, which were worn frequently by her late mother-in-law, Diana, Princess of Wales.