Princess Beatrice chose to honor Queen Elizabeth II with the name of her first child.
On Oct. 1, just under two weeks after she and Edoardo Mapelli Mozzi welcomed a daughter, Beatrice announced their baby girl's moniker. "We are delighted to share that we have named our daughter Sienna Elizabeth Mapelli Mozzi," she tweeted alongside an image of her daughter's footprints. "We are all doing well and Wolfie is the best big brother to Sienna."
Wolfie, whose real name is Christopher Woolf, is Edoardo's son from his previous relationship with architect Dara Huang.
Beatrice announced Sienna's birth two days after the baby's Sept. 18 arrival. "Her Royal Highness Princess Beatrice and Mr Edoardo Mapelli Mozzi are delighted to announce the safe arrival of their daughter on Saturday 18th September 2021, at 23.42, at the Chelsea and Westminster Hospital, London," Buckingham Palace said in a Sept. 20 statement. "The baby weighs 6 pounds and 2 ounces."
That same day, Beatrice's sister Princess Eugenie sent love to their growing family on Instagram. "To my dearest Beabea and Edo," she began, "Congratulations on your new angel. I can't wait to meet her and I'm so proud of you. We're going to have so much fun watching our children grow up."
Eugenie also sent a message directly to baby Sienna. "I love you already and think you're just awesome from the photos.. we're going to have so much fun together," she wrote. "Love your Auntie Euge."
In fact, Eugenie and Beatrice's kids are very close in age. Eugenie gave birth to son August, her first child, with Jack Brooksbank, in February, making the cousins' birthdays only seventh months apart.