The earliest guidebook to Windsor Castle – Bickham's Deliciæ Britannicæ (1742) – includes a description of the Guard Room of the Round Tower. ‘Over the Door-Way, going to the Dining Room are two Coats of Mail, belonging formerly to two Warlike Princes’. This watercolour depicts the room in c.1818, with rifles, swords, helmets and pikes arranged on the walls, as well as two half-armours above the doorposts, just as Bickham described. It is thought that one of the armours is the Greenwich armour of Henry, Prince of Wales (RCIN 72831) because of its distinctive decoration with thistles. In the twentieth century the arms and armour in the Round Tower were removed to make way for storage of the Royal Archives.