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The Danish royal family dressed to the nines on Monday to celebrate the birthday of a beloved sister, mother, and aunt at at Amalienborg Palace in Copenhagen.

Queen Margrethe II of Denmark threw a gala dinner in honor of the birthday of her younger sister, Princess Benedikte, who celebrated her 75th birthday on Monday.

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Benedikte reached for sentimental pieces of jewelry inherited from various family members for the dinner. Her diamond earrings are a legacy from her mother, the late Queen Ingrid of Denmark, while her necklace is part of the grand diamond sautoir that belonged to her grandmother, the late Queen Alexandrine. (More on that necklace here!) Her floral brooch, which can also be worn as a pendant, was a gift from her father, the late King Frederik IX.

Queen Margrethe chose shades of purple for her sister’s birthday dinner.

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She paired pearls with gorgeous amethyst and gold earrings, plus a carved hair comb.

Queen Anne-Marie, the youngest of the three Danish royal sisters, wore pieces from the former Greek royal family’s ruby set. (More on that parure here!)

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Benedikte’s nephew and niece, Crown Prince Frederik and Crown Princess Mary of Denmark, were also in attendance for the celebration.

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Like Anne-Marie, Mary wore family rubies for the occasion. (Learn more about the fascinating Danish royal rubies here!)

Here’s a better view of the ruby bracelet on her right wrist.

Benedikte’s daughters, Princess Alexandra of Sayn-Wittgenstein-Berleburg and Princess Nathalie of Sayn-Wittgenstein-Berleburg, also attended the dinner. Alexandra wore silver-toned jewelry with her coral-colored dress, including an intriguing leaf-shaped brooch. Nathalie chose golden jewels, including a prominent brooch. The sisters were escorted by Alexandra’s new partner, Count Michael Ahlefeldt-Laurvig-Bille. He’s a Danish noble, a longtime family friend — and, conveniently, Princess Benedikte’s godson.