The Hand Cannon was an early firearm, possibly one of the oldest in existence. It was the Special Weapon of Vlad the Impaler.
The hand cannon was simply a barrel with some kind of handle, although there were many variations. Most drawings depict it with a wooden stake supporting the barrel, with a wooden stock in the back. It had no trigger; the powder was lit through a touch hole on top of the barrel by means of a smoldering piece of wood or coal, or slow-burning matches.
The version shown in the show appeared to be little more than a barrel mounted on the front of a thick plank, with a handle on the bottom that doubled as a war spike.
The Hand Cannon was based on the Siege Cannon (which Vlad also used), but until the Hand Cannon was invented no one could develop a way to shrink the cannon's size while also making loading the weapon and producing musket balls possible.
China invented gunpowder in the 800s and created various prototype weapons during the Song Dynasty. The most noticeable was the Firelance; a barrel that used gunpowder to launch fire or shrapnel (akin to shotgun shot) out of the tube. Created in the 900s and popularized in the 1100s; these proto-guns came in various experimental sizes and shapes. As seen with the Nest of Bees; these guns were more effective against thick armies as they lacked the precision to fight individuals. Fire lances normally contained enough gunpowder for one massive shot; but reloading was difficult during the heat of battle.
The Nayan Rebellion of 1287 is cited as the first major conflict using Hand Cannons: however similar weapons did exist before this time period. The Heilongjiang hand cannon is an artifact believed to have been used in this same war. The 1320s and 1330s were the first reports of handcannons in Europe and by the late 1330s they gradually gained popularity throughout France. These guns most likely arrived in India and Arabia first. However due to Mongol Conquests; historical documentation in these countries were pillaged along with accounts of Hand Cannons.
By the mid to late 14th Century; Handcannons spread across nearly all of EuroAsia.
The Hussite Wars was one of the first major European wars involving handcannons. Hussite Waggon-Forts made several successful stands against Catholic Knights; with the handcannons demonstrating its vital armor-penetration stopping heavy plate-armored soldiers.
The hand cannon was possibly the oldest portable firearm to be used in battle. Although inaccurate and slow to reload, it was more powerful than any other weapon of its time, piercing even plate armor. It also had a spike on if so it could be used in melee combat (being roughly the medieval equivalent of a bayonet). In Europe, it was used until the 1520's, when more advanced matchlock Arquebus firearms replaced it.
After the fall of the Mongolian Empire, the hand cannon evolved into the 3-Barrel Pole Cannon to increase the rate of fire.
It was tested against the Huo Chien. It was given the edge due to the fact it could actually kill and had melee capabilities, while the flaming arrow proved to be highly ineffective.