Some time back I read a book called The Foundations of Early Modern Europe, 1460-1559. One thread I picked out as particularly clear was their explanation of the effects of gunpowder.
The first bit is what as known as pike and shot. Early gunpowder weapons were slow and inaccurate. But late medieval pike units had already changed warfare: not only could they withstand charges from knights, but they figured out how to charge themselves. Still, they weren’t as fast as knights, and there were ways to deal with them.
Pike and shot was the innovation that broke knights completely: early firearms would blow right through armor, and pikemen could protect the arquebusiers. Pike and shot units slaughtered knights.
The second issue is that gunpowder, or rather artillery, made medieval castles obsolete. Artillery enabled the conquest of both Normandy and Constantinople.
Thirdly, gunpowder at the beginning was very expensive. It “royalized” warfare, nobles couldn’t afford it, kings could, and they used it to destroy the independence of the feudal nobility: knights weren’t the dominant arm any more, castles couldn’t withstand sieges, and nobles couldn’t afford to upgrade their men to the new armaments in enough numbers.
The irony here is that gunpowder also “proletariatized” warfare: peasants could use guns just fine, without much training and pike work, while skilled, didn’t require the training of a knight. It was said that to truly train as a knight you had to start as a child, but a gunner or pikeman could be trained in a few months.
The result of all of this was larger armies, the breaking of the independent feudal nobility as independent military forces, and thus centralization. The full on absolutism monarchs like Louis the XIV “l’estat c’est moi” came later, but it’s this early process of gunpowder breaking the feudal nobility which allowed them to centralize power and turn the nobility into court aristocrats.
The loss of the nobles true source of power and their reduction into aristocrats (whose influence relies far more on their relation to the monarch than their own power) allowed for the rise of the early bourgeoisie. Feudal nobles had power because they had military force, and power trumped money, but as they lost that and as armies became much more expensive, money became a source of power all its own. Kings needed a lot of it to field the new armies, and the bourgeoisie had it. As a result a lot of bourgeoisie became nobles themselves, since owning land still had much more prestige than being a merchant, but over time it led to power moving away from the nobles, now an aristocratic courtier class, and to those with the money and that led rather directly to events like the English civil war and, later, the French revolution.
For those kings in-between, gunpowder must have seemed like a godsend: allowing them to break the troublesome nobles and centralize power, but it was a devil’s deal for them. The old feudal system was reasonably stable because knights were the decisive military arm, and knights and nobility were wrapped up together.
Once it was the king alone, surrounded by courtiers who had no real power themselves, but were parasites on the court, the days of Kings, too, were numbered.