Misercorde
Also known as the European dagger of mercy the Misercorde is a thin bladed dagger with a diamond section. It was used to administer a coup de grace on a fallen foe with the long thin blade being perfect for getting through helmet eyeholes and breathing slits.
How to cite this article:
Dugdale-Pointon, TDP. (19 April 2004), Misercorde, http://www.historyofwar.org/articles/weapons_misercorde.html