Royal beasts were originally heraldic supporters and badges used by monarchs. The beasts at Windsor represent the houses of Lancaster and York; both descended from King Edward III; that were reunited by the marriage of Henry VII to Elizabeth of York and the birth of their son, later Henry VIII.
There are a total of seventy six beasts on the roof; forty two holding vanes (flags) on the pinnacles of the clerestory parapet and thirty four bearing shields. There are two further beasts at the base of the West Steps leading to the West Door; the Lion of England and the Unicorn of Scotland which both bear the Royal Arms.