Princess Beatrice broke family rule when naming her daughter

While the focus this week has been on President Trump's unprecedented second state visit, Princess Beatrice has a major reason to celebrate today as her and Edoardo Mapelli Mozzi’s eldest daughter Sienna turns four today (September 18). While it is not known how the family plan to celebrate, there is no doubt that Sienna will enjoy her special day.

Although not much is known about the young royal, especially as her mum isn’t a working member of the Firm and is careful not to allow her daughter to be pictured very often, Sienna’s name has always sparked interest. This is because her name is a nod to her father’s Italian heritage.

Her name is also believed to be a nod to her grandmother and Princess Beatrice’s mum Sarah Ferguson by beginning with an 'S'.

This was revealed by a family friend, who told Hello!: "They (Beatrice and Edoardo) were looking for an Italian name which started with an S for Sarah, to honour the Duchess [Sarah Ferguson], and also reflected the golden rust colour of both the Duchess's hair colour and Beatrice's, which the new baby shares.”

However, while Sienna’s name has plenty of sentimental meaning, it has been reported before that Beatrice, 37, actually broke a family tradition with this name.

This is because before Beatrice named Sienna, her immediate family had used a family naming tradition started by her mum Sarah, Duchess of York.

This tradition was to name children with a nod to Queen Victoria, something Sarah did when naming Beatrice and Eugenie, with Beatrice also being the name of Queen Victoria's youngest daughter, while Eugenie’s name - and middle names - were also connected to the late monarch.

Although Eugenie, Beatrice’s sister, has continued this naming tradition with her own sons, with her son August sharing one of Queen Victoria’s husband’s given names, and her other son Ernest being a nod to Queen Victoria's brother-in-law, this is not something Beatrice has done.

While the family naming rule is not officially enforced, and has never been mentioned by Beatrice or her immediate family, it may have been a surprise for her mum Sarah Ferguson.

Since the birth of Sienna four years ago today, Beatrice and her husband have since welcomed her second daughter Athena Elizabeth Rose into the world earlier this year.