William I, also known as William the Lion, was the first King of the Scots to use a unicorn as part of his coat of arms during the 12th century. It still is Scotland’s national animal. In Celtic mythology, this fictitious horse with a spiral horn represents purity and innocence plus rule by harmony. This heraldic panel is attached to a walled-in gatehouse at the Palace of Holyroodhouse. It is the royal arms of James V, the king who commissioned the palace in the early 16th century.