The arquebus was the first shoulder-fired firearm with a mechanical ignition, emerging gradually from the hand cannon during the fifteenth century.
The arquebus is the first firearm that a soldier could hold to his shoulder, aim along, and fire without taking a hand off the weapon. That single change — mechanical ignition — separates it from the hand cannon it grew out of.
It emerged gradually through the fifteenth century rather than at a stroke. Stocks improved, the touch hole moved from the top of the barrel to the side, a small pan was added to hold priming powder, and a pivoting arm was fitted to bring a burning match down to it. The mature weapon is a late-fifteenth-century object.
It belongs in a medieval archive because that whole sequence happens inside the Middle Ages, even though the weapon's great career comes afterwards. The arquebus is the last thing the medieval battlefield produced and the first thing the early modern one inherited.
The starting point is the hand cannon: a barrel on a stick, with the touch hole bored through the top, fired by touching a hot wire or a match to it by hand. The shooter cannot aim while doing that, and often needs a second man.
Three changes fix it, and they arrive separately over decades. The stock is shaped so the weapon can be held to the shoulder or cheek rather than braced under the arm. The touch hole moves to the side of the barrel and gains a small pan to hold priming powder. And the match is fitted into a pivoting arm — the serpentine — so a lever brings it to the pan.
The result is not a new invention but an accumulation. Any given surviving gun may have one, two or all three of these features, which is precisely why the terminology is so unstable and why no single date can be given for the arquebus appearing.
The serpentine is the whole breakthrough, and it is mechanically trivial: an S-shaped iron arm, pivoted on the side of the stock, with a clamp at the top holding a length of smouldering slow match.
Pressing a lever underneath rotates the arm forward and down so the burning tip of the match dips into the priming pan. The priming powder flashes, the flash passes through the touch hole into the main charge, and the gun fires.
What this buys is aim. Both hands stay on the weapon, both eyes stay on the target, and the shooter is no longer reaching across his own barrel with a piece of burning cord. Early forms are simply a lever and an arm; the developed matchlock adds a spring and a sear so the arm snaps rather than being pushed.
Barrels are forged iron or cast bronze depending on date and maker, generally 70 to 100 centimetres and smoothbore, of roughly 15 to 20 millimetres calibre. There is no standardisation: guns were made individually and bores vary within a single arsenal.
The stock is wood, and its evolution is the visible history of the weapon. Early ones are barely more than a straightened tiller; later fifteenth-century stocks are shaped to sit against the shoulder or the cheek, which is what makes aiming possible at all.
The barrel is held to the stock by iron bands or pins, and the lock — pan, serpentine, lever, and on later examples a spring and sear on a lock plate — is set into the right side of the stock. There is no rear sight, no trigger guard, and no safety of any kind; those all belong to later centuries.
Powder is measured into the muzzle, a lead ball follows, and both are rammed down onto the breech. A little fine powder goes into the pan beside the touch hole, and the pan cover — where one is fitted — is closed over it.
The slow match, a length of cord soaked in saltpetre solution, is kept burning throughout. It is clamped into the serpentine, its tip blown to a bright coal, and the weapon is brought up.
Pressing the lever swings the match into the pan. The priming flashes, fire passes through the touch hole, and the main charge fires. The whole cycle takes around a minute, and every step of it is vulnerable to rain, wind and a match that has gone out.
It was an infantry weapon used from prepared positions and in formation, and its natural home in the fifteenth century is the siege and the fortified field position rather than the open manoeuvre battle.
Its great tactical advantage over the crossbow and the bow is not performance but supply. A handgunner is useful within weeks, so an army can be expanded far faster than one depending on trained archers, and the same argument that had favoured the crossbow now told against it.
It develops in step with the pike. Handgunners have no defence at all while reloading, so they need something to stand behind, and the pairing of shot with pike blocks that dominates the sixteenth century is already visible in Burgundian and Italian practice in the fifteenth.