The Cambridges
Prince William and Kate Middleton have no custody of their children. Pictured: Prince George, Prince William, Kate Middleton, Princess Charlotte and Prince Louis after the latter's christening at St James's Palace on July 09, 2018 in London. Getty Images/Dominic Lipinski

Prince William and Kate Middleton have no custody of their children.

This might be surprising to many, but the Duke and Duchess of Cambridge have no custody of 5-year-old Prince George, 3-year-old Princess Charlotte, and 3-month-old Prince Louis. Prince Harry and Meghan Markle will also have no custody of their future kids, according to royal historian and expert Marlene Koenig.

"The sovereign has legal custody of the minor grandchildren," Koenig told News.com.au. "This goes back to King George I [who ruled in the early 1700s], and the law’s never been changed. He did it because he had a very poor relationship with his son, the future King George II, so they had this law passed that meant the King was the guardian of his grandchildren."

According to Koenig, the law is already 300 years old when the majority of 10 out of 12 judges in 1717 agree the monarch's "right of supervision extended to his grandchildren and this right or right belongs to His Majesty, King of the Realm even during their father's lifetime."

Koenig explained that this law still stands today. In fact, when the Duke of Sussex and Duke of Cambridge were still children, Prince Charles had to ask the Queen if he could take them together to Scotland.

"Technically, they needed permission for travel. The Queen has the last word on parenting decisions like that," Koenig explained.

In related news, Prince William and Middleton had asked the Queen's permission when they took Prince George in their trip abroad. However, it was done not due to their lack of custody but because the family has a travel rule prohibiting two heirs from boarding the same flight at the same time. This is reportedly done so the royal lineage would not be affected in case of a crash. Prince William is second-in-line to the throne while his eldest son is the third successor.

Prince William and Middleton are expected to continue breaking this protocol for Prince Louis. Royal commentators believe that it is likely that they would take their youngest child on a trip abroad the way they have done it to Prince George and Princess Charlotte. But, then again, they would have to ask the Queen's permission to do so.