War hammers were developed as a consequence of the plate armour of the fourteenth and fifteenth centuries. Armors, being so elaborate and made of thick steel, proved excellent defence against swords, which tended to ricochet off the armors' non flat surfaces. Swords, or the blade of a battleaxe, were likely only to give a glancing blow, losing much of the impact, especially on the high curvature of the helmet. As a consequence, the War hammer was created to puncture armors and cause considerable damage and kill openents, event heavily armored oponents.
War hammers, especially when mounted on a pole, could damage without penetrating the armour. In particular, they transmitted the impact through even the thickest helmet and caused concussions. A blade or spike tended to be used against other parts of the body where the armour was thinner, and penetration was easier, than through the helmet. The spike end could be used for grappling the target's armour, reins or shield.
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