All the Pictures of Queen Elizabeth, Prince William, and Princess Anne at the Order of the Thistle

Queen Elizabeth has spent the last week in Scotland for Holyrood Week, her annual tour of Scotland. Though she was under the weather a week ago in London, she seemed in great spirits today for the bi-annual Order of the Thistle in Edinburgh.

Every other year, the Queen appoints new members to the order in recognition of "men and women who have held public office or have contributed significantly to national life." The Queen, her husband the Duke of Edinburgh (who has retired from official public duties), her daughter Princess Anne, and Prince William (known in Scotland as the Earl of Strathearn) are all Royal Knights of the Thistle as well. (The Duchess of Cambridge did not attend for the second time in a row.)

The order may or may not have been founded a millennia ago when King Achaius formed an alliance with the Emperor Charlemagne. Another theory holds that James III founded the order about 500 years ago, but its official beginning happened under James II.

All the Knights (royal and those earning their recognition for the first time) get to wear the green robes, insignia, and plumed hats. Accompanied by the Band of the Royal Regiment of Scotland, the Knights process along a route in Edinburgh to the Thistle Chapel in St. Giles's Cathedral, where they are installed in the order by the Queen.