The bombard was the great siege gun of the fourteenth and fifteenth centuries, built to batter down walls that no earlier weapon could bring low.
A bombard is a very large gunpowder cannon built for one purpose: to knock down a wall. It appears in Europe in the fourteenth century and dominates siege warfare through the fifteenth, and it is the weapon that closes the medieval period.
Everything about it is subordinated to that single task. It is enormous, it is almost immobile, it shoots a few times a day, and it is not expected to hit anything smaller than a curtain wall — none of which matters if the wall comes down.
It did what nothing before it could. Siege engines could batter a wall for months; a bombard battery could open a breach in days, and the change was fast enough that European fortification had to be redesigned from first principles.
Two methods were used. The older builds the barrel from longitudinal wrought-iron staves held by shrunk-on iron hoops — the same construction as a wooden barrel, and the reason a gun barrel is called a barrel at all. The other casts the gun whole in bronze, which is stronger and far more expensive.
The scale is difficult to overstate. Calibres of thirty to eighty centimetres are normal for the largest, weights run past sixteen tonnes, and the shot is dressed stone rather than iron, because a stone ball of that size is cheaper and does not need a perfect bore to fit.
Many are built in two pieces — a barrel and a separate powder chamber — that screw or wedge together, which makes an otherwise unmovable object transportable and lets the chamber be made thicker where the pressure is greatest.
A bombard is emplaced, not manoeuvred. It travels in pieces on carts or barges, is assembled in a prepared position within range of the target wall, and stays there until the siege ends.
Rate of fire is measured in shots per day for the largest pieces. The gun must cool, be swabbed, reloaded and re-laid, and the crew must be confident it will not burst — so a battery works by patient repetition against one section of wall rather than by weight of fire.
Its decisive moment is 1453. At the Fall of Constantinople Ottoman bombards, including guns cast for Mehmed II by the Hungarian founder Orban, broke the Theodosian Walls that had held for a thousand years, and in the same year at the Battle of Castillon French guns in a fortified park destroyed John Talbot's attacking army.
Its strength is that it solves a problem nothing else could. A high stone wall was, before gunpowder, close to impregnable to anything but starvation or treachery; a bombard battery reduces it to a matter of weeks.
Its weaknesses are immobility, cost and danger. It is useless in a field battle, it consumes vast quantities of expensive powder, and it kills its own crews with some regularity — James II of Scotland was killed in 1460 when a gun burst beside him while he was besieging Roxburgh.
It is also at the mercy of the weather and the roads. Powder spoils in damp, and moving a sixteen-tonne gun across medieval roads in winter is simply not possible, which tied the great guns to the campaigning season.
Small gunpowder weapons appear in Europe in the first half of the fourteenth century, and guns grow steadily larger through it as founders learn what their materials will take.
The giant bombards belong to the first three-quarters of the fifteenth century — Mons Meg was cast in 1449, the Dardanelles Gun in 1464 — and they represent the peak of the "bigger is better" approach to siege artillery.
They are then superseded quickly. Longer, lighter cast-bronze guns firing iron shot proved more accurate, more mobile and more destructive than a giant stone-throwing bombard, and by the end of the century the huge guns were obsolete curiosities.
Flanders and Burgundy produced some of the largest European guns, and Dulle Griet at Ghent survives from that tradition. The Holy Roman Empire produced Faule Mette at Brunswick and the Pumhart von Steyr, which has the largest calibre of any surviving bombard.
Scotland has Mons Meg, made in Flanders in 1449 and given to James II — a reminder that great guns were diplomatic gifts as much as weapons, since very few rulers could have one made.
The Ottoman tradition worked in cast bronze at a scale nobody in Europe matched, and the Dardanelles Gun is the outstanding survivor: two bronze halves that screw together, cast in 1464 by Munir Ali.