A battle axe (also battle-axe or battle-ax) is an axe specifically designed for combat. Battle axes were specialized versions of utility axes. Many were suitable for use in one hand, while others were larger and were deployed two-handed.
Axes designed for warfare ranged in weight from just over 0.5 kg to 3 kg ( 1 to 6 pounds), and in length from just over 30 cm to upwards of 1.5 m (1 to 5 feet), as in the case of the Danish axe or the sparth axe. Cleaving weapons longer than 1.5 m would arguably fall into the category of polearms.
Through the course of human history, commonplace objects have been pressed into service as weapons. Axes, by virtue of their ubiquity, are no exception. Besides axes designed for combat, there were many battle axes that doubled as tools. Axes could be modified into deadly projectiles as well (see the francisca for an example). Axes were often cheaper than swords and considerably more available.
Battle axes generally weigh far less than modern splitting axes, especially mauls, because they were designed to cut legs and arms rather than wood; consequently, slightly narrow slicing blades are the norm. This facilitates deep, devastating wounds. Moreover, a lighter weapon is much quicker to bring to bear in combat and manipulate for repeated strikes against an adversary.
The crescent-shaped heads of European battle axes of the Roman and post-Roman periods were usually made of wrought iron with a carbon steel edge or, as time elapsed across the many centuries of the medieval era, steel. The hardwood handles of military axes came to be reinforced with metal bands called langets, so that an enemy warrior could not cut the shaft. Some later specimens had all-metal handles.
Battle axes are particularly associated in Western popular imagination with the Vikings. Certainly, Scandinavian foot soldiers and maritime marauders employed them as a stock weapon during their heyday, which extended from the beginning of the 8th century to the end of the 11th century. They produced several varieties, including specialized throwing axes (see francisca) and "bearded" axes or "skeggox" (so named for their trailing lower blade edge which increased cleaving power and could be used to catch the edge of an opponent's shield and pull it down, leaving the shield-bearer vulnerable to a follow-up blow). Viking axes were wielded with one hand or two, depending on the length of the plain wooden haft. (See entry for Viking Age arms and armor.)