Caltrap

Caltrap, Caltrop, Galtrap, or Chevaltrap. This last rendering (though not the most generally accepted form of the name) is a ready explanation of the term. Caltraps are by no means unfrequent charges in heraldry, and were made of iron, each with four points so placed that whichever way the instrument might lie upon the ground one point would be always erect. They were formerly used in warfare, and thrown in the way, to prevent the enemy's cavalry pursuing an army on its retreat. When the point is bloody it is termed "embrued at the point." The caltraps in the compartment standing upon which the supporters of the Earl of Perth are depicted, with the motto "Gang warily," are said to be borne in commemoration of the defeat of the English - due in a large measure to the use of these weapons - at the battle of Bannockburn.