Prince William is stepping out on what would have been the 65^th birthday of his late mother, Princess Diana.

William, or the Duke of Rothesay as he’s titled in Scotland, was at the Order of the Thistle service at St. Giles’ Cathedral, in the heart of Edinburgh, Scotland, July 1. The 44-year-old wore the deep green velvet robe and black hat trimmed with flamboyant white ostrich feathers while attending the service alongside other senior royals.

He arrived with his uncle, Prince Edward, shortly before his father, King Charles, 77, and Queen Camilla, 78, who were welcomed with a Royal Salute given by The King’s Body Guard for Scotland (Royal Company of Archers), and the playing of God Save the King.

Outside the cathedral, anti-monarchy protesters held up placards asking ‘What Did You Know?’ at the royals and chanted “Not my King.”

The Most Ancient and Most Noble Order of the Thistle is the greatest order of chivalry in Scotland and is considered the highest honor in the nation. It recognizes 16 Knights and Ladies, men and women who have contributed significantly to national life. The King, Queen Camilla as well as Edward, the Duke of Edinburgh, and Princess Anne are all members of the order alongside William.

The decision was made in 1987 by Charles’ late mother, Queen Elizabeth, to open up the order to women as well.

The service is similar to the annual Order of the Garter event, which takes place at Windsor each June. This year’s event came on the day that William’s beloved Princess Diana would have been 65. She died in 1997 following a car crash in Paris, France.

On June 30, William marked the latest stage in his initiative to help the homeless, a campaign he was inspired to take up by his mother. Part of the day was spent in the northeastern Scottish city of Aberdeen, which is one of the flagship locations for his Homewards project, where they are piloting new initiatives to tackle homelessness.

Diana immersed both William and his brother, Prince Harry, 41, in her commitment to help the homeless, taking them to shelters and charities when they were young. It is something William has adopted, forging his own path with his project Homewards, selling a magazine on behalf of the unhoused and introducing his son Prince George to the work over Christmas 2025.

The Order of the Thistle service that William attended on July 1 took place during Royal Week in Scotland, which kicked off with Charles taking part in the Ceremony of the Keys to mark his arrival at the Palace of Holyroodhouse.

On Tuesday, June 30, he and Camilla, 78, also hosted a garden party at the royals’ official Scottish home. Camilla also met with author J.K. Rowling, as she highlighted her ongoing bid to increase literacy among children.

However, their meeting courted controversy as it came during Pride month, due to Rowling’s history of anti-trans comments.