The war hammer was a late medieval striking weapon built to damage armor through impact, piercing, or both.
The war hammer is a late-medieval weapon combining a hammer face with a curved rear spike, mounted on a short haft for one hand or a long one for two. It is a purpose-built answer to plate armour and appears when plate does.
It solves the armour problem twice over. The hammer face delivers concussion through the plate, and the spike concentrates enormous force on a single point to punch through it or to hook and drag.
It belongs to the fifteenth century above all, the period in which a fully armoured man-at-arms was the hardest target on the battlefield and the whole armoury was reorganising around him.
The horseman's hammer runs 50 to 70 centimetres with a head of 0.8 to 1.5 kilograms; two-handed versions on hafts of 1.2 metres or more shade into polearm territory and are usually classed with the poleaxe family.
The head has two working faces. The hammer is often serrated or studded so it bites rather than glances off a curved plate, and the rear spike — the beak or fluke — curves downward to a point, so that the wielder's pulling motion drives it in rather than skidding.
Better examples have langets, iron straps running down the haft from the head, which stop an opponent cutting the shaft and stop the head loosening. Some hafts are entirely of steel, which removes the weak point altogether.
It was used by armoured men against armoured men, mounted and on foot, and belongs to the same tactical world as the poleaxe and the rondel dagger: weapons for beating a harness rather than for beating a man.
The hammer face was used against helmets and the large curved surfaces of the harness to stun and disable, while the spike went for the thinner or less well-supported places — the joints, the back of the helmet, the shoulder.
The spike also functioned as a hook. It could catch a limb, a shield rim or a helmet and drag a man off balance or off a horse, and once he was down the fight moved to grappling and the dagger.
Its great strength is that it addresses armour two ways at once, so the wielder chooses his method against whatever part of the harness he can reach. Nothing else in the armoury is as flexible against plate.
Its weakness is reach. The one-handed hammer is very short, and its user has to get inside the range of almost every other weapon on the field to use it, which is why it belongs to men who were themselves well armoured.
It is also poor against an unarmoured opponent, where a sword is faster, longer and more versatile — a specialist weapon that is close to useless outside its specialism.
It emerges in the fourteenth century alongside the spread of plate defences, and the timing is not a coincidence: the weapon exists because the target changed.
The fifteenth century is its mature period, when it becomes standard cavalry equipment across Western and Central Europe and appears throughout the art of the Hundred Years' War and the Burgundian wars.
It persists into the sixteenth century, and the two-handed forms — the Lucerne hammer among them — remain in Swiss and German infantry service after the mounted hammer had begun to fade.
German and Central European workshops produced the most developed forms, including all-steel hafts and elaborately shaped beaks, and the war hammer is particularly prominent in Imperial and Hungarian contexts.
French and Burgundian sources show it constantly in the hands of mounted men-at-arms, and the horseman's hammer became close to a badge of that class in the fifteenth century.
Swiss infantry developed the long-hafted Lucerne hammer, which sits between the war hammer and the polearm and was used in the massed pike formations where reach mattered more than handiness.