Royals attend Order of the Thistle ceremony

From left, Queen Elizabeth II, Prince Philip, Duke of Edinburgh, Prince William and Princess Anne leave the Signet Library to head to St Giles' Cathedral for the Thistle Ceremony on July 5, 2012, in Edinburgh, Scotland, where Prince William was installed as a knight of the historic Order of the Thistle.

Princess Anne leaves the Signet Library to head to St Giles' Cathedral for the Thistle Ceremony on July 5, 2012, in Edinburgh, Scotland, where Prince William was installed as a knight of the historic Order of the Thistle.

Prince Philip, Duke of Edinburgh, leaves the Signet Library to head to St Giles' Cathedral for the Thistle Ceremony on July 5, 2012, in Edinburgh, Scotland, where Prince William was installed as a knight of the historic Order of the Thistle.

Queen Elizabeth II, center, accompanied by Prince Philip, Duke of Edinburgh, right, Princess Anne, left, and Prince William attend the Thistle Service at St Giles' Cathedral in Edinburgh, Scotland, for the installation of Prince William as a knight of the Thistle on July 5, 2012.

Queen Elizabeth II, left, accompanied by Prince Philip, Duke of Edinburgh, right, attend the Thistle Service at St Giles' Cathedral in Edinburgh, Scotland, for the installation of Prince William as a knight of the Thistle on July 5, 2012.

Prince Philip, Duke of Edinburgh, right, Princess Anne, left, and Prince William, Duke of Cambridge, attend the Thistle Service at St Giles' Cathedral in Edinburgh, Scotland, for William's installation as a knight of the Thistle on July 5, 2012.

Queen Elizabeth II, left, accompanied by Prince Philip, Duke of Edinburgh, right, attend the Thistle Service at St Giles' Cathedral in Edinburgh, Scotland, for the installation of Prince William as a knight of the Thistle on July 5, 2012.

Kate, Duchess of Cambridge, leaves St Giles' Cathedral after the Thistle Ceremony on July 5, 2012, in Edinburgh, Scotland. Prince William, Duke of Cambridge, was installed into the historic Order of the Thistle in a ceremony in Edinburgh attended by the Queen Elizabeth II and Duke of Edinburgh.

Kate, Duchess of Cambridge, talks to Lady Sarah Chatto as she leaves St Giles' Cathedral after the Thistle Ceremony on July 5, 2012, in Edinburgh, Scotland. Prince William, Duke of Cambridge, was installed into the historic Order of the Thistle in a ceremony in Edinburgh attended by Queen Elizabeth II and the Duke of Edinburgh.

Prince William and Princess Anne leave the Thistle Ceremony at St Giles' Cathedral on July 5, 2012, in Edinburgh, Scotland, after William was installed as a knight of the Order of the Thistle.

Queen Elizabeth II leaves St Giles' Cathedral after the Thistle Ceremony on July 5, 2012, in Edinburgh, Scotland, where Prince William was installed as a knight of the historic Order of the Thistle.

Prince William leaves St Giles' Cathedral after being installed as a knight of the historic Order of the Thistle in Edinburgh, Scotland, on July 5, 2012.

Kate, Duchess of Cambridge, leaves St Giles' Cathedral after the Thistle Ceremony on July 5, 2012; in Edinburgh, Scotland. Prince William, Duke of Cambridge, was installed into the historic Order of the Thistle in a ceremony in Edinburgh attended by Queen Elizabeth II and Duke of Edinburgh.

Kate, Duchess of Cambridge, leaves St Giles' Cathedral after the Thistle Ceremony on July 5, 2012, in Edinburgh, Scotland, where Prince William was installed as a knight of the historic Order of the Thistle.

Queen Elizabeth II smiles as she leaves St Giles' Cathedral after the Thistle Ceremony on July 5, 2012, in Edinburgh, Scotland.

Prince William leaves St Giles' Cathedral after he was installed as a knight of the historic Order of the Thistle in a ceremony on July 5, 2012, in Edinburgh, Scotland.

Queen Elizabeth II leaves St Giles' Cathedral after the Thistle Ceremony on July 5, 2012, in Edinburgh, Scotland. Prince William, Duke of Cambridge was installed into the historic Order of the Thistle in a ceremony in Edinburgh attended by the Queen and the Duke of Edinburgh.