Kate Middleton was on hand to support her husband.

Prince William attends Garter Day at Windsor Castle on June 15, 2026.Credit : Jordan Pettitt – WPA Pool/Getty

Just two days after gathering for Trooping the Colour, the British royals are marking another longstanding tradition.

On Monday, June 15, the royals convened at Windsor Castle for the annual Order of the Garter service, celebrating Britain’s oldest and most senior order of chivalry. The Order is celebrated each year with a procession and service on the grounds of Windsor Castle, the British royal family’s ancestral home.

Prince William, King Charles, Queen Camilla and more wore blue velvet robes and ostrich feather-plumed hats for the ceremony, which dates back to 1348. King Edward III “was so inspired by tales of King Arthur and the chivalry of the Knights of the Round Table that he set up his own group of honorable knights, called the Order of the Garter,” the royal family’s website says.

King Charles and Queen Camilla attend Garter Day at Windsor Castle on June 15, 2026.Toby Shepheard/WPA Pool/Getty

Kate Middleton and Sophie, the Duchess of Edinburgh, are not in the Order of the Garter, but they attended the event, as they have in years past, to support their husbands. The royal women were seen standing along the procession route and chatting while they waited for the procession. They then smiled and waved as they saw their spouses.

Kate Middleton and Sophie, the Duchess of Edinburgh on Garter Day at Windsor Castle on June 15, 2026.Chris Jackson / POOL / AFP/Getty

The Order used to be limited to the aristocracy, but members are now selected from a variety of backgrounds in celebration of their public service, with both men and women welcomed.

The membership is exclusive to King Charles, who is the Sovereign of the Garter, several senior members of the royal family and 24 knights and ladies recognized by the monarch for their public service.

Prince Edward and Prince William at Garter Day at Windsor Castle on June 15, 2026.Aaron Chown / POOL / AFP/Getty

Today’s royal group of Garter members includes Queen Camilla, Prince William, Princess Anne, Prince Edward, Princess Alexandra, the Duke of Kent, the Duke of Gloucester and the Duchess of Gloucester.

The event has been held annually since 1948, and at the annual service, the sovereign invests any new Companions with the Order’s insignia in the Throne Room of Windsor Castle. The Garter members and officers then attend a lunch hosted by the monarch, and then all walk to a service at St. George’s Chapel, where new Companions are installed. After that short service, the monarch and members of the Order then return to the Upper Ward of the castle via carriages and cars.

Princess Anne at Garter Day on June 15, 2026. Aaron Chown/WPA Pool/Getty

Ousted from the group is the former Prince Andrew, who lost his royal titles and more in late 2025. King Charles made the decision to strip his brother’s honors in light of renewed scrutiny around Andrew’s ties to the late Jeffrey Epstein; Andrew has denied any wrongdoing regarding their relationship.

Garter Day at Windsor Castle on June 15, 2026.HENRY NICHOLLS / POOL / AFP/Getty

The Garter Day parade is held each year in June, coming shortly after another staple on the royal calendar: Trooping the Colour, which had its annual parade in honor of the monarch’s birthday on Saturday, June 13, this year.

SOURCE: https://people.com/prince-william-king-charles-wear-feathered-hats-garter-day-inspired-by-king-arthur-11996619