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This weekend, the British press caught Prince Harry’s girlfriend, Meghan Markle, watching him play in the Audi Polo Challenge. The appearance was reminiscent of some of Kate Middleton’s polo pop-ups before her engagement to Prince William, and the outing has set the rumor mill racing.

I think it’s safe to say that Harry’s relationship has entered very serious territory, so you know what that means: it’s time to start a little good-natured premature speculation about Meghan’s royal wedding tiara! 😉 Here are my four choices from the royal vaults…

Meghan’s style tends toward the sleek and modern, so I think one of the coolest options available would be the triple-bracelet bandeau once owned by the Queen Mother. Made by Cartier, the set features five Deco-style interchangeable bracelets: two set with only diamonds, one set with diamonds and rubies, one set with diamonds and emeralds, and one set with diamonds and sapphires. Although the piece hasn’t been worn in public as a tiara since the 1930s, the Queen still owns and wears the individual bracelets, and I have a feeling the tiara fittings for the piece are still around in the royal vault. Perhaps Meghan could wear diamonds and sapphires, conveniently donning something old (antique), borrowed (from the Queen), new (to her!), and blue?

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On the opposite side of the tiara spectrum is the Strathmore Rose, the delicate floral tiara that the Queen Mother received as a wedding present from her parents. There are persistent rumors that the tiara, which hasn’t been worn in public in decades, is in disrepair, but it was photographed for Hugh Roberts’s diamond book in 2012 and looked to be in excellent condition. If Meghan wants to go bohemian for her wedding, the tiara includes one frame that allows it to be worn across the forehead; she could go for an “English rose” look with the piece’s second frame, which situates it more traditionally atop the wearer’s head.

One of the most glam tiaras lurking in the royal vaults is the diamond and sapphire bandeau worn by Queen Mary and Princess Margaret. The piece is said to have come from the jewelry collection of Empress Marie Feodorovna of Russia, and it features a single sapphire in a cluster of diamonds, flanked on either side by a frame with a diamond sunray design. The diadem would be one of the most unusual royal wedding tiaras worn by a Windsor bride, but it would be a stunning statement.

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Two Windsor brides — the Queen and Princess Anne — have worn this diamond fringe tiara on their wedding days. It’s currently owned by the Queen, but it was made for Queen Mary almost a century ago. The Queen has only worn it once in public since inheriting it from the Queen Mother in 2002, and loaning it to Meghan would be a clear sign of royal approval. It’s also both classic and packed with diamonds, the perfect marriage of sleek and sparkling for a modern princess.