King Charles and Queen Camilla have officially welcomed President Donald Trump and first lady Melania Trump to their second state visit to the U.K.

The Trumps were received by Kate Middleton and Prince William after their helicopter, Marine One, landed on the grounds of Windsor Castle on Wednesday, Sept. 17. They then walked with the Prince and Princess of Wales to be officially welcomed by the King and Queen.

During the greetings, some observers noted that the president, 79, did not bow and the first lady, 55, did not curtsy while shaking hands with Charles and Camilla, as well William and Kate.

But is this actually a breach in royal protocol? Not according to the royal family’s official website, which states, “There are no obligatory codes of behaviour when meeting a member of the Royal Family, but many people wish to observe the traditional forms.”

It goes on to explain, “For men this is a neck bow (from the head only) whilst women do a small curtsy. Other people prefer simply to shake hands in the usual way.”

The explanation was referenced back in 2018, when Trump also shook hands with Queen Elizabeth instead of bowing.

The following year, during the U.S. president’s first official state visit, he notably put his hand on the Queen’s back at the state banquet, provoking more debate about whether or not he broke royal protocol.

Trump, however, departed from U.S. protocol during Wednesday’s royal reception. After the group was escorted by carriage by the Household Cavalry Mounted Regiment, military bands from the Royal Marines, Army, and Royal Air Force played both the British and U.S. national anthems.

As the U.S. anthem played, Trump performed a military salute. According to 36 U.S. Code § 301, only individuals in uniform, service members, or veterans are supposed to salute.

“All other persons present,” the code states, “should face the flag and stand at attention with their right hand over the heart.”

President Trump’s visit to the U.K. will also include a state banquet on Wednesday night, as well as a Thursday meeting with U.K. Prime Minister Keir Starmer at his country home, Chequers, in Buckinghamshire.

Additionally, Melania will join Princess Kate for their first joint engagement on Thursday, visiting Frogmore Gardens in Windsor. There, they’ll join the U.K.’s Chief Scout Dwayne Fields and members of the Scouts’ Squirrels program as youngsters explore nature while earning their “Go Wild” badge.

Kate, who was a Brownie as a child, has served as Joint President of the Scout Association since 2020.