Also riding in the ceremony for the first time was the Duke of York in his new role as Colonel of the Grenadier Guards.
Among the guests was Defence Secretary Gavin Williamson, the Prime Minister Theresa May normally attends but is at a G7 meeting of world leaders in Canada.
For those unfamiliar, the Trooping of the Colour is the most highly-anticipated event in the royal calendar (well, aside from last month's Royal Wedding, of course) and is steeped in English tradition. Flags, or colours, were "trooped" so soldiers in the ranks would be able to recognize them.
The Trooping the Colour is a ceremony performed by regiments of the British and Commonwealth armies to mark the official birthday of the British sovereign. Although Queen Elizabeth already turned 92 on April 21, the royals understandably prefer to party and socialize in warmer weather.