Warhammers were developed as a consequence of the ever more prevalent metal armours of the medieval battlefields during the 14th and 15th centuries. The war hammer could deal blows of tremendous force to the target, especially when mounted on a pole, and by impact alone do damage without penetrating the armour. The spike end could be used for grappling the target's armour, reins, or shield, or could be turned in the direction of the blow to pierce even heavy armour. Against mounted opponents the weapon could also be directed at the legs of the horse, toppling the armored foe to the ground where they could be dealt with.
The most famous war hammer is Mjollnir, the favourite weapon of the Norse god, Thor.