The War Hammer was a bludgeoning weapon used in medieval Europe. It was the Close-Range weapon of William Wallace.
War hammers ranged in size from barely bigger than a carpenter's hammer, such as the one shown in Deadliest Warrior, to pole weapons the length of halberds. The head had a flattened end for smashing and often a curved spike for impaling. Like many pole weapons, the war hammer had langets, strips of metal attached to the handle to protect it from blows.
As surface-hardened armor became increasingly prevalent on the battlefield, swords and axes were more likely to deflect off the armor without causing damage. The war hammer allowed the user to damage without penetrating the armor as a strong blow to even the strongest helmet could still transfer enough energy to cause a concussion. The spiked end could be used to grapple the opponent's armor or shield, and could pierce even heavy armor. Longer hammers were used against mounted opponents, while shorter hammers were used in close quarters and from horseback.