Double-Headed Battle Axe

• Double-headed battle axes, as evident from their names, were used as weapons in battles. Reportedly, they have been in use since the stone age.
• Europeans, specifically viking warriors, were the first ones to create an axe just for battles. The need for battle axes arose when swords proved to be ineffective against plate armor; that's why "maces, axes and war hammers were preferred by foot soldiers during the Middle Ages. Shorter handled axes were favored by knights for mounted combat."
• Although many accounts, like this and this, report battle axes to be used for battle (as the name would also suggest), there are speculations that battle axes were never used for battle and have just been adopted in the modern world as a heroic tool of war. Instead, these were used for two other purposes, namely to cut wood and as ceremonial axes.

The Boat Axe

• Many noticeable cultural transformations and migrations took place in the neolithic era across Europe. Among those was a middle neolithic complex in Scandinavia that resembled the Continental Corded Ware Culture (CWC), namely the Battle Axe Culture (BAC).
• The Battle Axe Culture was also known as the Boat Axe Culture in Sweden.
• The BAC "was distributed in Scandinavia up to modern-day Middle Sweden and southern Norway and on the eastern side of the Baltic Sea up to the southwestern parts of Finland" after it started around 3000/2800 BCE.
• The Boat Axe Culture is a subgroup in the Nordic Single Grave Culture, named after "the use of a slender type of stone battleaxe shaped like an upturned boat."

The Polygonal Axe

• The polygonal axe is a battle axe that belongs to the late stone age around 3000-3400BC.
• The axe is usually fitted with a shaft hole and made from greenstone or another exclusive stone.
• The axe has "various special features, such as a flared edge, an arched butt, an angled body, grooves and ridges."