Earliest pratical military usage of Gunpowder

[Zor]

As we all know, black powder is made of three main ingredients....

-Carbon (most notably Charcoal)
-Sulfer
-Potassium Nitrate (Saltpeter)

All of which have been used specifically for various purposes by Human Civilization for thousands of years and humans have been toying around with combinations of diferent materials for just as long. It is quite conceivable that Black Powder could been stumbled upon thousands of years ago. Never-the-less, Black Powder has only been in use for little more than a thousand years and its use in military purposes only really kicked off in the 15th century, which was not outstandingly more advanced than the Roman Empire and if you went back in time to the time of Caeser with a napoleonic bronze cannon and a crew for it, Demonstrated its ability to turn buildings into so much rubble, told him how it worked, how to make gunpowder and handed him the blueprints for such a device, it's a safe bet that within a few years the Roman Legions would be filled with Cannons with legionaries gleefully blowing Gauls and Goths into piles of Gore.

Now here is the big question, what was the earliest point in history in which Gunpowder could be developed and used militarially? Could it have been that the Greek City States supplemented their hoplites with Arquebuses? Could the Kings of Babylon repelled the Assyrians with salvos from Bronze Cannons? What was the soonest time frame in which Gunpowder could have emerged as a primary weapon of war?

Zor

[Sea Skimmer]

Gunpowder weapons would mean becoming dependent on centralized logistics for the production of cannon and fresh powder. Transportation of both would be a serious limitation, cannon are heavy, gunpowder has to be kept dry and doesn’t store for long periods. Nitrates meanwhile have to be produced in a process that typically took about 18 months, you can’t just find them in the field (outside of a handful of areas on earth anyway). The Romans wooden siege engines meanwhile could be built on the spot, using a handful of ropes and metal parts brought along. All of this means gunpowder will greatly reduce the mobility of the Legions, and that’s bad news for the Roman Empire.

I’m pretty confident they could do it, well cannons anyway, making matchlocks might be too much, but I’m not very confident it would have been of any practical advantage. In fact it might work against Rome in the long run. Rome depended on a core of professional soldiers, and while the total Roman army was big, no single Roman force in the field was. The real advantage of gunpowder firearms meanwhile was that it let you raise a mass army quickly, and such armies will threaten the Empire more the defend it. Cannon are much better then catapults for smashing down walls… but only if you have big hard to move cannon, and after all did Rome EVER face a fortress it couldn’t take already?

[Fingolfin_Noldor]

Wasn't it until the Italian wars when the French king invaded that gunpowder weapons start to show some teeth? Prior to that, bombards were only good for shelling fortresses, like the siege of Constantinople, and the Ottoman sieges of Malta. You will need some serious innovations in metallurgy for gunpowder to be useful on the field.

[Thanas]

The Romans wooden siege engines meanwhile could be built on the spot, using a handful of ropes and metal parts brought along. All of this means gunpowder will greatly reduce the mobility of the Legions, and that’s bad news for the Roman Empire.

You are correct about the majority of siege weapons, however not when talking about long range artillery.

Rome depended on a core of professional soldiers, and while the total Roman army was big, no single Roman force in the field was.

Compared to the average battle up to the Napoleonic wars, the numbers are way lower compared to Roman times. Battles in the Thirty years war, for example, routinely were conducted between forces numbering well below a Roman legion. The forces at the battle of Lützen, where the swedish king Gustav Adolphus died, numbered about 19.000 on the League and 20.000 on the Reich side. Each of those armies are way smaller than the smallest Roman army in the field (about 24.000 men, composed of 2 legions plus auxillaries, client people and vexillations). The Romans hardly ever sent legions alone in the field, and the only offensive action of that kind I can think off without looking at the books is Vespasians II Augusta during the second invasion of Britain.

Cannon are much better then catapults for smashing down walls… but only if you have big hard to move cannon, and after all did Rome EVER face a fortress it couldn’t take already?

There are a few fortresses Rome couldn't take, though that was more due to external factors such as logistics or revolts than to the fortresses themselves.

[Thanas]

Wasn't it until the Italian wars when the French king invaded that gunpowder weapons start to show some teeth? Prior to that, bombards were only good for shelling fortresses, like the siege of Constantinople, and the Ottoman sieges of Malta. You will need some serious innovations in metallurgy for gunpowder to be useful on the field.

Gunpowder weapons were used to great effect in the Hundred Year Wars. The Battle of Castillon is widely considered to be the first battle where gunpowder artillery were the deciding factor. Ironically, it happened on July 17th, 1453, less than two months after the fall of Constantinople on May 29th.