Royals Princess Beatrice and Edoardo Mapelli Mozzi Attend Art Fair One Month After Welcoming Daughter Sienna Princess Beatrice was chic in a trench as the royal couple attended the Frieze London Art Fair at Regent's Park By Stephanie Petit Stephanie Petit Stephanie Petit is a Royals Editor, Writer and Reporter at PEOPLE. People Editorial Guidelines Published on October 13, 2021 04:03PM EDT Edoardo Mapelli Mozzi and Princess Beatrice. Photo: Dave Benett/Getty It's a royal parents' day out for Princess Beatrice and Edoardo Mapelli Mozzi! Less than one month after welcoming their daughter Sienna Elizabeth, Queen Elizabeth's granddaughter and her husband smiled for a photo at Ned's Club Lounge at Frieze London Art Fair on Wednesday. It marks one of their first public outings since their family's new addition (Edo, as Beatrice's husband is called, is also a father to a son named Christopher Woolf from a previous relationship). Sienna was born on September 18 at the Chelsea and Westminster Hospital in London, but the couple didn't announce her name until October 1 — along with a sweet photo of the baby's footprints. While it's obvious to the baby girl's middle name is a sweet tribute to Beatrice's grandmother Queen Elizabeth, the first name Sienna was a more unexpected choice — the latest odds after the birth had the frontrunners as Matilda, Florence, Arabella, Cecelia and Francesca. Sarah Ferguson, Now a Grandmother of Two, Says Grandson August 'Finds Me Very Funny' Instead Beatrice, 33, chose a name that incorporated several thoughtful nods to her mother, Sarah Ferguson (or "Fergie," as the Duchess of York is affectionately called), including the hue of the locks mother, daughter and now granddaughter share. "They were looking for an Italian name which started with an S for Sarah, to honour the Duchess, and also reflected the golden rust colour of both the Duchess's hair colour and Beatrice's which the new baby shares," a source told Hello! magazine. Princess Beatrice and Edoardo Mapelli Mozzi. Luc Castel/Getty Sienna 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." Princess Beatrice had another reason to celebrate this week: it was her sister Princess Eugenie third wedding anniversary with husband Jack Brooksbank on Tuesday. Can't get enough of PEOPLE's Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more! Eugenie — who welcomed her first child, a son named August, in February — marked the occasion by sharing a previously unseen photo from her wedding day. In the photo, she is dancing closely with Jack and has a broad smile on her face.