News.com.au and The Sun are reporting that technically, Kate Middleton and Prince William do not have legal custody over their children, Prince George, Princess Charlotte or Prince Louis due to a 300-year-old royal law that gives custody to the sovereign, aka the queen. This law applies to all minor grandchildren and means that Meghan Markle and Prince Harry will have to deal with it, too, when and if they decide to have children. “This goes back to King George I (who ruled in the early 1700s), and the law’s never been changed," royal historian and expert Marlene Koenig told News.com.au. "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.” That law was passed in 1717 and hasn't been changed. That means the queen does have a say in decisions regarding George, Charlotte and Louis's education, upbringing and traveling. But Koenig added that the palace “doesn’t make a big deal” out of the law these days. When Charles becomes king, he will have technical custody of his grandchildren but isn't likely to override major decisions. He is “very respectful of his son’s parenting," Koenig said. “He understands they want to raise their children privately … the only thing Charles might ask for is more pictures,” she added in jest.Constitutional expert Michael L. Nash echoed Koenig's points in "The Times" in 1993, per The Sun, when discussing Princess Diana's influence over Harry and William's upbringing. He wrote that the "Queen has the last word in the custody upbringing, education and even the right of abode of the princes, even during the lifetime of their father, Prince Charles. As for their mother, the Princess of Wales, her say is a matter of discretion and negotiation."