Buckingham Palace has promised that the upcoming coronation of King Charles and Queen Camilla will be as much an homage to tradition as a signal of a new modern era for the House of Windsor. How exactly that will all translate may not be clear until the actual event on May 6, but we got a little taste of their intentions last month when it was announced that Camilla would be breaking from centuries of tradition to recycle a former consort's crown for her coronation rather than commission one of her own.

Queens consort since the 18th century have had exclusive tiaras made for these occasions, a practice that began in 1761 with Charlotte, who didn't want to follow her precedessors' leads by wearing Mary of Modena's 1685 topper. But this, after all, is the 21st century, and spending such a sum on a diamond-laced extravagance to wear just once isn't exactly a modern way of doing things.

king george v and queen mary 1911
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A 1911 coronation portrait of King George V and Queen Mary.

In dipping into the archives of former consort crowns, the natural choice might have been the Queen Mother's, Camilla's direct predecessor in this job, were it not for a glaring problem: the diamond sparkling front and center, otherwise known as the Koh-i-Noor, a 105.6-carat symbol of Britain's colonial history. The controversial gem was presented to Queen Victoria in 1850 as one of the spoils of war following the two Anglo-Sikh Wars and has been the subject of ownership disputes since 1947, when India gained independence from the UK.

So in the interest of avoiding yet another scandal for the Firm, Camilla has opted instead for Queen Mary's 1911 crown. (Technically speaking, the Koh-i-Noor graced the original version of this crown, too, before it was removed to be used for the Queen Mother's, where it has remained since.) Considering Mary's reputation as the most formidable jewelry collector in Windsor history, this feels like a fitting choice for the new queen, who herself is no amateur in this department.

the state crown of queen mary
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Queen Mary’s crown originally featured the controversial Koh-i-Noor diamond before it was removed to be used in the future Queen Mother’s crown in 1937.

Designed by royal jeweler Garrard for the coronation of King George V and Queen Mary in June 1911, the crown is set with 2,200 diamonds, producing an effect so brilliant the Daily Telegraph once wrote of it: "...the diamonds cluster together as if they had no support but their own light." It's decorated with fleur-de-lys and cross-pattée motifs, features a frieze of quatrefoils and rosettes, and has eight arches topped off with a pavé-set monde with a cross above it. And, like most Windsor gems, it's built for versatility. The arches can be removed so the piece can be worn as a circlet, which is what Mary did for her son's coronation in 1937.

king george vi and his wife queen elizabeth
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Queen Mary wore her crown, sans arches, for the coronation of her son and daughter-in-law, King George VI and Queen Elizabeth, in 1937.

Camilla is making a few edits of her own. The arches will be pared down to four and two famous Cullinans will be returned to their original places: the 94.4-carat pear-shaped Cullinan III and the 63.6-carat square-cut Cullinan IV, which Mary had removed post-coronation (and replaced with rock crystal replicas) to use elsewhere, most notably as the brooch that later became one of her granddaughter's favorite gems, Queen Elizabeth's "Granny's Chips." And, skirting the Koh-i-Noor problem, that center spot will instead be taken up by the 18.8-carat heart-shaped Cullinan V, whose most recent iteration was as a brooch also much beloved by Elizabeth. These diamonds will be making their first appearance since the queen's death in September.

With the mystery of Camilla's crown solved, we're now left to speculate on what Princess Kate will choose for this historic occasion. A round of Tiara March Madness, anyone?

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Leena Kim
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Leena Kim is an editor at Town & Country, where she covers travel, jewelry, education, weddings, and culture.