The early history of the gun is quite obscure. There is a reference in an old chronicle which could be interpreted as suggesting that firearms were used at the siege of Forli in Italy in 1284. But this is extremely vague and subject to alternative interpretations. A generation later there is an Arabic manuscript which describes several different types of firearms and prescribes a powder of 74% saltpeter, 14.8% charcoal, and 11.2% sulphur, but it cannot be dated with any greater accuracy than to some time after 1304. Moreover, the manuscript makes some comments which suggest that the author was not personally familiar with firearms. Then there is an item in the chronicles of Ghent in Belgium for 1313 to the effect that one Berthold Schwartz, a friar from Breisgau in Germany, had in that year invented "bussen," that is "guns"; but there are several linguistic and stylistic oddities about the reference, which suggest that it was probably inserted some centuries after the fact. It is only in the 1320s that references to firearms begin to become reliable. Guns of some sort were definately used at Metz in 1324, and a Florentine document dated 1326 makes use for the first time of the word "cannon," deriving from the Latin "canna," meaning "reed," an obvious reference to the tubular construction of such devices.
In 1327 King Edward III of England (reigned 1327-1377) appears to have brought some cannon along on an invasion of Scotland. This campaign gives us our first picture of an early gun, in the Millemete Manuscript, a document in the library of Christ Church College at Oxford. The manuscript is an illuminated copy of a speech commemorating the King's success in the field. In one of the margins is depicted a vase-like object lying on a kind of table. A man in armor is holding a match against the bulbous base of the piece and an arrow-shaped projectile is emerging from the muzzle. Known in Italian as a "vaso" (pot or vase) and in French as a "pot de fer" (iron-pot), such primitive cannon must by then have been relatively commonplace. Over the next few years references to firearms begin to proliferate, and it appears that they were known everywhere in Europe, classified as a form of artillery, a term then including all missile weapons. It seems probable that gunpowder and cannon were first used in attack on and in the defense of fortified places.
The first use of gunpowder weapons in sieges was apparently in the form of hand-bombs which could be hurled down on the heads of the attackers by the defenders, or hurled by the attackers at the defenders, using catapults and trebuchets, ancient war engines which continued in use right into the Renaissance. These were fine in an anti-personnel role, but were not particularly useful for smashing into a place. More useful was the mine, a variant of the ancient art of tunneling under a fortification in order to undermine the walls, with the addition of gunpowder. This was time consuming and not very safe, but continued in use well into the Twentieth Century.
Another device which proved of some value was the petard, French for "little fart". The petard was essentially a big, heavy gauge metal pot filled with powder. It was used to blow in the doors of fortified places. A team of unusually heroic men would run the thing over to the gate, fasten it firmly in place by means of long nails from which the petard hung by its handles, light the fuse, and then run for cover. When the petard went off, its heavy construction would tend to direct the explosive force against the door, smashing it down and thereby permitting one's men to storm in with sword or axe in hand. In practice, the petard was not particularly efficient. For one thing, the men hauling it up to the gate were subject to the lethal attentions of the defenders. Moreover, its effectiveness, marginal at best, could be easily dissipated if it was not securely fastened in place. And premature explosion was sufficiently common as to add to the language the phrase "Hoist by his own petard."
Like rockets, hand bombs, explosive mines, and petards were weapons of limted utility. Because of this, they continued in use for special tasks right into the Twentieth Century. Indeed, the rocket, the mine, and the hand bomb have had something of a renaissance in this century. The petard has not fared so well, though its last appearence was as recently as 1903, when the Serbian officers who assassinated King Alexander Obrenovich (reigned 1889-1903) and his rather distasteful queen. used one to gain entry into the Royal Palace. True to its reputation, the petard "hoist" the man who set it off.
But neither the rocket, nor the mine, the hand bomb nor the petard, could compare with the cannon. The weapon which rather quickly eclipsed them was a rather modest-sized device normally firing a stone or iron ball, or even a heavy arrow.
Early cannon were not very large. Evidence suggests that pieces weighing 600 pounds were considered "heavy" guns. Yet while not particularly useful against the walls of the more serious types of fortifications, castles and towns, these early cannon were fairly effective at battering down the walls of the lesser places, the fortified manor houses and towers. As these types of places were the bastions of the petty lords, who could ill-afford more massive works, the first social effect of gunpowder was to further reduce the already curtailed independence of such individuals, to the benefit of the greater lords and ultimately to that of the crown, both of whom could afford more extensive defenses and, incidently, cannon of their own. Cannon were also far better than petards at smashing the gates of even the most stoutly built places. Since cannon could batter a way into a fortress without recourse to a lengthy siege, the attacker was relieved of the necessity of maintaining a large besieging army, thereby saving both money and time. The popularity of cannon was thus assured. But there were problems with early cannon.
The first cannons were not very safe. Many were made of wooden staves reinforced with metal straps. Others were built up of wrought iron bars welded together and bound with hoops, and some were even made of cast iron. Quality was problematic and guns burst with great frequency. So poor were the pieces, that technical progress in the chemistry of gunpowder lagged. It appears that the optimal proportions for the ingredients in gunpowder were at least experimentally known by the mid-14th Century. However such efficient mixtures could not be used in practice since they would burst anything one tried to use them in. Things began to improve around mid-century when the casting of guns in a bronze of about 10% tin was developed at Augsburg in Germany, making use of technology originally developed for bell making.
But bronze was so much more expensive than iron that the latter persisted despite its greater weight and poorer safety. In the 1340s, a modest sized bombard of about 300 pounds net weight, capable of hurling stone balls of perhaps two or three pounds, cost upwards of 1,800 ducats if made of iron, and much more in bronze. Hand-hewn stone cannon balls, long produced for catapults (which continued in use for over a century after the introduction of cannon), ran as much as 20 ducats each. Gunpowder ran some 35-40 ducats a pound, with saltpeter being the dearest ingredient, about 45 ducats a pound due to its great scarcity . Sulphur, which had to be imported everywhere save in Italy, was about 20 ducats a pound. Charcoal was the cheapest component, costing only 2-3 ducats a pound.
The gun crew had to be paid, at 10 ducats or better per man per day. Thus, a relatively modest number of rounds from a single bombard could cost over a thousand ducats. Of course, the effects of such might well be worth the expenditure. Moreover, the price tended to fall as technology and experience improved. Cannon got better, with improvements in metallurgy, the introduction of lead and iron shot, and advances in the production of gunpowder. The primary spur to this progress was the Hundred Years War.