Prince William was made a Royal Knight of the Garter on Monday at a ceremony presided over by his grandmother the British monarch and attended by his father, brother and girlfriend.
Queen Elizabeth II made William the 1,000th knight to join the order and formally presented him with the regalia, including a blue garter, sash and star brooch.
After the ceremony at Windsor Castle, the knights wore their traditional ostrich feather hats and velvet robes as they walked to St. George's chapel in the castle grounds.
William's girlfriend Kate Middleton, watched the procession with his brother Prince Harry.
The Order of the Garter was established in 1348; the monarch can give the honor to anyone she chooses.