The celebration of a milestone birthday for one of Europe’s best-loved monarchs, plus a glittering assembly and the surprise appearance of a brand-new tiara? Not a bad way to start off a Thursday! Here’s a rundown of the guests who attended Queen Margrethe’s birthday gala at Christiansborg Palace.

The birthday girl wore a tiara that she’s worn at a number of important events in her life: her mother’s Floral Aigrette Tiara. She arranged the three parts of the tiara in an interesting configuration: one of the pieces was nestled in her hair just like a normal tiara would be, while the other two were arranged on the sides of her hair.

Margrethe paired the aigrette with jewelry from one of the four sets of Danish crown jewels: the ruby, diamond, and pearl parure, most of which was made in 1840 by C.M. Weisshaupt. The pearl necklace that Margrethe wore at the gala is even older: it belonged to Charlotte Amalie of Hesse-Kassel, who was Denmark’s queen consort from 1670 to 1699. She’s also wearing the earrings and the top part of the large devant de corsage from the set.

Crown Princess Mary wore pieces from Desiree Clary’s ruby set, including the tiara, the hairpins, the earrings, the bracelet and the ring.

Here’s a view of the way that Mary incorporated the hairpins into her ‘do.

Princess Marie wore familiar pieces of jewelry: Princess Dagmar’s Floral Tiara, sapphire and diamond earrings, and Queen Alexandrine’s sapphire and diamond pendant.

Princess Benedikte wore the Sayn-Wittgenstein-Berleburg Fringe Tiara, pairing it with the diamond necklace made from part of one of Queen Alexandrine’s sautoirs. The floral brooch she wears can also be used as a pendant on a necklace. Her diamond earrings are from Queen Ingrid’s collection.

Queen Anne-Marie wore the diamond necklace that is the twin of Benedikte’s necklace — both come from Queen Alexandrine’s sautoirs. She’s incorporated the necklace into the jewels from the Greek emerald parure, which features stones that Queen Olga brought with her from Russia.

Princess Elisabeth, as usual, wore the diamond and sapphire tiara that once belonged to Princess Thyra of Denmark.

Countess Sussie of Rosenborg, from the junior branch of the Danish royal family, wore Queen Alexandrine’s Fringe Tiara, pairing it with modern jewelry.

Queen Silvia of Sweden led the parade of foreign monarchs and consorts, wearing the glittering Leuchtenberg Sapphire Parure.

Queen Maxima of the Netherlands wore the family’s diamond bandeau tiara and diamond earrings.  

At her waist, she secured her order sash with the large diamond bow brooch from the Stuart parure.

Queen Mathilde of the Belgians glittered for the first in the full version of the Nine Provinces Tiara. She’d previously only worn the bandeau base. She paired the tiara with her diamond and pearl wedding earrings.

But the biggest surprise of the evening by far came courtesy Queen Letizia of Spain, who debuted a brand-new tiara at the gala. She wore the diamond and pearl tiara made for her by Ansorena, which features a large, detachable fleur-de-lis at the center. She’d previously worn that part of the tiara as a brooch, but we’d not seen the entire piece until this event.

As I wrote on the blog last night, the tiara’s genesis has been shrouded in mystery a bit, but we know that it was made for Letizia and acquired around 2009. Some reports say that Felipe bought the tiara for his wife as a wedding present, but Ansorena has gone on record that they made the tiara and gave it to the princess as a gift from the firm. Accepting presents from outside entities has always been a tricky business for royals — especially royals reigning in a country dealing with economic instability — so there may be a reason that Letizia waited for a foreign, non-state event to debut the piece.

Letizia wore the new tiara with earrings made of diamonds with pendant pearls, as well as her Cartier diamond bracelet and a small diamond brooch pinned to her sash. And, even more intriguingly for Letizia’s jewel-watchers, she also appears to be wearing a wedding ring, something she hasn’t done in public for quite some time.