The Princess Royal listens to speeches during a party at Windsor Castle, given by the Queen in honour of her 50th birthday and attended by guests from charities and organisations for which the Princess is patron. * Anne, 50, was being installed as a Royal Lady of the Thistle at Edinburgh's St Giles' Cathedral. The Order of the Thistle is Scotland's highest honour and premier order of chivalry. The colourful ceremony in the Scottish capital brings together senior Royals as the Queen bestows the important accolade on her daughter in recognition of her work, flying the royal standard north of the border. Also in Scotland for the Thistle ceremony was the Duke of Edinburgh, and the Prince of Wales, using his Scottish title of Duke of Rothesay.