King Charles III inspects troops in Horse Guards Parade

Britain's King Charles III Charles inspected the troops at his inaugural birthday parade on horseback Saturday, the first time the monarch has ridden at the event since his mother, Queen Elizabeth II, in 1986. The annual Trooping the Colour parade marks the British sovereign's official birthday.

The colourful display of regimental precision and pageantry is the first of 74-year-old Charles's reign. Charles's actual birthday is on November 14 but British sovereigns celebrate twice -- once in private and again in public. The June parade tradition began in 1748 under King George II.