Prince William and Kate Middleton only have one daughter in their brood of four — Princess Charlotte Elizabeth Diana. However, the source of her name is the subject of speculations among royal family fans because it was never publicly revealed whom she was named after.

It’s easy to see where the young princess’ second name came from. The second name “Elizabeth” is a nod to both her great-grandmother, Queen Elizabeth II, and her great-great-grandmother, the late Queen Mother. It’s also a tribute to her mom herself, who was born as Catherine Elizabeth Middleton.

It is likewise quite obvious where Charlotte’s third name came from. It’s a touching tribute to the grandmother she never met, Diana, Princess of Wales.

What’s a bit confusing, however, is where William and Kate got the inspiration from for their only daughter’s first name, Charlotte. Thankfully, royal family fans are an imaginative bunch and would naturally have a theory or two about the matter.

There are those who believe that the name actually came from William and Harry’s father, Prince Charles. “I think the couple named their daughter Charlotte as a mark of respect to Prince Williams father Charles,” Sharon Ann Cummins-Royes wrote on Quora. “Charlotte is the feminine of Charles.”

Meanwhile, some suspect that the name might even be a reference to one of King George IV’s children. “She may have been named after HRH Princess Charlotte Augusta Of Wales who was the only child of HRH George, Prince of Wales (later HM King George IV) and his wife Caroline Of Brunswick,” Quora user Jade Welch wrote.

“HRH The Princess Charlotte was pressured by her father to marry William, Hereditary Prince of Orange (later King of the Netherlands). After initially accepting him, HRH The Princess Charlotte soon broke off the intended match,” she added.

There’s also the possibility that she might be named after queens consort of the past. For instance, Queen Charlotte of Mecklenburg-Strelitz, wife of King George III, was the queen consort of the United Kingdom of Great Britain and Ireland.

In coming up with the name of her only daughter, Kate most likely had a say in the matter as well. Thus, some fans believe that the name “Charlotte” might also be a nod to her sister, Pippa. “It is also interesting to note that HRH The Duchess of Cambridge’s sister (Pippa Matthews) middle name is Charlotte,” Quora user Elizabeth Anne Nield wrote.

Princess Charlotte Princess Charlotte of Cambridge. Getty Images