LONDON (CNN) -- With all the pomp and ceremony befitting her station, Britain's Queen Elizabeth II was feted Saturday during the official celebration of her 72nd birthday.

Although the queen was actually born on April 21, the birthdays of British monarchs have been celebrated in June since Queen Victoria first did so in 1843. The highlight of the day is Trooping the Color, an elaborate military pageant.

The queen road alone in an open carriage from Buckingham Palace to the ceremony, behind another carriage carrying Queen Mother Elizabeth and Princess Margaret, the queen's sister. Riding behind the queen, three abreast, were her son, Prince Charles; her husband, Prince Philip; and the Duke of Kent.

Despite intermittent rain, the crowd gathered to watch Queen Elizabeth pass was three deep along both sides of the Mall.

It was the first celebration of this important event on the monarchy's ceremonial calendar since the tragic death of Princess Diana last August, which put the royal family under intense public scrutiny.

Trooping the Color dates back nearly two centuries, to an era when each military leader needed his own flag, or colors, to stand out clearly during battle. Regular "trooping" allowed soldiers to recognize the flags around which they should rally.

Later in the day, the queen joined her family on the balcony of Buckingham Palace to watch a variety of modern and historic aircraft fly by overhead.