The practice began in seventeen forty eight when King George the Second decided to combine the annual summer military march with his own birthday festivities. He was also born in November, so the arrangement suited him. Edward the Seventh, who was born in the same month, followed the same pattern.

The habit lasted. For more than two and a half centuries, Trooping the Colour has marked the official birthday of the reigning monarch. The King’s Birthday Parade features more than fourteen hundred soldiers, two hundred horses, and around four hundred musicians.

What This Means for Prince William

Royal watchers have pointed out an interesting detail regarding the next generation. Prince William was born on June twenty first. If he follows tradition once he becomes King, his real birthday would fall so close to Trooping the Colour that he may not need two separate dates.

He might choose to celebrate only one birthday. Or, he might enjoy two parties a week apart. No one would blame him for that, since the option is right there.

For now, King Charles continues the long established custom, enjoying both his November birthday and his official celebration each June.