What is Trooping the Colour? Here's everything you need to know about the royal birthday celebration

King Charles took center stage at his first Trooping the Colour parade on Saturday.

The streets were lined with crowds hoping to catch a glance at the royal family, while over 1400 soldiers, 200 horses, and 400 musicians were in attendance to honor the momentous day. The parade moved from Buckingham Palace down The Mall to Horse Guard's Parade, with the royals navigating the streets on horseback and in carriages.

What is Trooping the Colour?

The annual celebration has marked the official birthday of the British Sovereign for over 260 years. (While King Charles' birthday is actually November 14, Trooping the Colour traditionally takes place each June to embrace the sunny June weather.) It originally took its name from traditional preparations for battle, but in the modern day, the pomp and circumstance is a grand celebration of the royal family and "a great display of military precision, horsemanship, and fanfare," per the official site for the royal family. The entire display concludes with a massive Royal Air Force fly-past, while the royal family watches from the balcony of Buckingham Palace.

Who was in attendance

As the honoree of the celebration, King Charles, 74, held center court throughout the day. Riding through the streets on horseback, he was joined by his son Prince William, his brother Prince Edward, and his sister Princess Anne as they trotted through the streets of London in royal garb.

Queen Camilla, 75, who took on an honorary position as Colonel of the Grenadier Guards back in January, wore a red silk dress that reflected the heritage of the infantry regiment of the British Army, the BBC reported. Designed by Fiona Clare, the outfit included "The Grenade Fired Proper" embroidered in gold bullion on the collar and back. The ensemble was completed with a hat designed by Philip Treacy, with whom she frequently collaborates. Many fans on social media expressed surprise at Camilla's untraditional outfit choice.

Alongside Queen Camilla, Kate Middleton rode in the carriage through the streets of London. Sporting a bright emerald green ensemble designed by Andrew Gn and a Philip Treacy hat, some said the outfit paid tribute to the late Queen Elizabeth's appearance at last year's Jubilee Ceremony, Town & Country reported.

Prince William and Princess Kate's children also joined their mother and step-grandmother to cruise through the streets for the occasion. As expected, Prince George, 9, Princess Charlotte, 8, and Prince Louie, 5, stole the show, smiling as they sat in the carriage and later took the balcony of Buckingham Palace.

Following the performance of military bands and the escorted Regimental Colour, or flag, being processed down the ranks of soldiers, the occasion was concluded when the entire family came together to watch the Red Arrows of the Royal Air Force Aerobatic Team cascade through the sky in a stunning show. There was also a 41-gun salute fired in Green Park to mark the occasion.

Who Was Not in Attendance

Charles' other son, Prince Harry, was notably absent despite being a decorated military veteran. However, People reported that he and his wife Meghan Markle were not invited to attend the celebration, despite being in attendance last year.

Instead of joining the rest of the family on the balcony in 2022, Prince Harry and Markle watched from the Major General's Office, which overlooks the Horse Guards Parade. At the time, the Queen had announced beforehand that only senior members of the royal family would appear on the balcony of Buckingham Palace.