Princess Beatrice Reveals Newborn Daughter's Name — Find Out How She Paid Tribute to the Queen

Princess Beatrice has announced her baby girl's name!

She has chosen the name Sienna Elizabeth Mapelli Mozzi. "We are all doing well and Wolfie is the best big brother to Sienna," she added in the tweet announcing the news.

Naturally, royal watchers will instantly spot that the baby's middle name is a tribute to Queen Elizabeth, and Beatrice is following suit with several of her royal cousins: Prince William's daughter is named Charlotte Elizabeth, and Prince Harry's daughter is named Lilibet after the Queen's childhood nickname. Siblings Zara Tindall and Peter Phillips also gave their daughters the middle name Elizabeth.

Beatrice, 33, welcomed her first child with husband Edoardo Mapelli Mozzi on September 18.

Edo, as he's affectionately called, wrote his own touching name announcement on Instagram Friday: "Our life together has just begun, and I can't wait to see all the amazing things that await us."

He continued, "Feeling so much love and gratitude for my amazing wife, baby Sienna and Wolfie. These are the days I never want to forget. This week, a friend said to me the sweetest saying….that with every child you grow a whole new heart 💖"

The baby girl will also have a royal title — and not because Beatrice's grandmother is the Queen! Edo descends from Italian aristocracy — which means that Princess Beatrice became an Italian "Contessa" and "Nobile Donna," or noble woman, after their July 2020 wedding.

Edo's father is Count Alessandro Mapelli Mozzi, and as his oldest son, Edo will inherit the family's ancestral seat, the 18th-century Villa Mapelli Mozzi palace in northern Italy.

"Edoardo is the only male descendent taking the family into the next generation," his father previously told The Daily Mail. "He is a count — his wife will be a countess automatically and any of their children will be counts or nobile donna."

Immediately following the birth announcement of Princess Beatrice's daughter, betting odds put the names Matilda, Florence, Arabella and Cecelia as top predictions. (Elizabeth was also a frontrunner.)

"It should come as no surprise to see that punters are backing slightly more unusual names for the new royal baby given Beatrice and her sister's monikers," Jessica O'Reilly of Ladbrokes said. "Matilda and Florence are proving popular names at the top of the betting, along with other Italian-inspired choices such as Arabella and Giovanna."

Princess Beatrice's younger sister, Princess Eugenie, welcomed her first child earlier this year with husband Jack Brooksbank. The couple named their son August Philip Hawke, revealing the special meaning behind his moniker on Instagram.

"He is named after his great grandfather and both of his great x5 grandfathers," Eugenie, 31, explained.

The name August means "great, magnificent." The baby boy got his first name from Queen Victoria's husband Prince Albert, who was born Franz Albert August Karl Emanuel. The rest of his moniker comes from a 5x grandfather on Jack's side, Rev. Edward Hawke Brooksbank. Philip is a tribute to Eugenie's grandfather Prince Philip, who died in April at age 99.

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The royal family's new addition — she is currently 11th in the line of succession to the British throne — is Queen Elizabeth's 12th great-grandchild and the second grandchild for Sarah Ferguson and Prince Andrew.