The Duke of Sussex has revealed that his older brother, Prince William, was “jealous” of him in the days leading up to his 2018 wedding to Meghan Markle—and for an unexpected reason.

Prince Harry and Meghan exchanged vows on May 19, 2018, at St. George’s Chapel, Windsor Castle. While William supported his brother on the big day, Harry claims they had a significant disagreement beforehand.

Harry, like William at his own wedding in 2011, wore his military uniform. However, unlike his older brother, Harry was allowed to keep his beard—a decision that reportedly upset William. According to military protocol, Harry should have been clean-shaven while wearing the frock coat uniform of the Blues and Royals. However, Harry requested and received special permission from the Queen to keep his beard for the occasion, something that allegedly angered William.

In his memoir Spare, Harry detailed the incident, calling it “beard-gate.” He wrote, “And yet I now dared to make another ask—Granny, please, may I, for my wedding, keep my beard? Not a small ask either. A beard was thought by some to be a clear violation of protocol and long-standing norms, especially since I was getting married in my Army uniform. Beards were forbidden in the British Army.”