The Platinum Jubilee, celebrating 70 years on Her Majesty's throne, was a royal first. And in that spirit, there was another important royal first: three Cambridge children, Prince George (8), Princess Charlotte (7), and Prince Louis (4), made their carriage debuts this morning in the Trooping the Colors parade.

Riding across from their mothers, Catherine, Duchess of Cambridge, and Camilla, Duchess of Cornwall, the three Cambridges waved to the gathered crowd as they rode down the mall in their carriage. Kate wore a white Alexander McQueen dress (re-worn) and a white and blue Philip Tracy hat, while her three children coordinated in blue. George wore a suit, white collared shirt, and blue tie; Charlotte wore a blue dress with transparent sleeves; and Louis wore a sailor-style white and blue outfit.

Although her actual birthday is in April, Trooping the Colors is an official celebration of the Queen's birthday that takes place every June. This year's Trooping the Colors is especially significant because it not only celebrates Her Majesty's 96th birthday, but also marks the landmark 70th anniversary of her ascension to the throne.

According to PEOPLE magazine, Prince William, Duke of Cambridge, the father of the Cambridge children, made his carriage debut in 1987, a few weeks before his fifth birthday. The young prince wore a pale blue coat and rode with his mother, Princess Diana, and his great-grandmother, the Queen Mother. Prince Harry was also four years old when he made his "Trooping the Colors" debut, riding with his brother, mother, and great-grandmother.

This is also the first time that George, Charlotte, and Louis have participated in a carriage procession, but they have all appeared on the balcony of Buckingham Palace to watch the Royal Air Force flypast.