In the campaigns of the Hundred Years War, Edward III's troops took many French towns by surprise and scaling ladders. But if surprise and simple assault failed, little else seems to have worked. Until the final war years and the coming of strong cannon, the besiegers seem to have had almost no luck breaking down defended walls.
Yet even before cannon, besiegers had learned to breach castles with mining or counterweight trebuchets. The English kings weren't any strangers to this: King John's Dover Castle was briefly broken into by mining in 1216, and Edward I breached the walls of Caerlaverock in 1300 and Stirling in 1304 with siege engines.
So what happened to English siegecraft?
Sieges weren't as common in the Hundred Years War as in some others, but there were still a fair number -- Calais 1346, Rennes 1356, Reims 1359, etc. But those sieges seem to have been remarkably lacking in siege engineering, compared to the wall-breaching work of Dover 1216 or Stirling 1304. Why?
I can think of six possible answers, but I don't know which, if any, are true:
Yes, mining or counterweight trebuchets could breach walls, but only if the attacker had exceptionally large numbers or favorable circumstances. The Dover and Stirling cases above reflect extraordinary weight of numbers or good luck.
To build mines or trebuchets, you need trained siege engineers. Non-royal sieges like Rennes had nobody on hand with the skills required. As for the king's own sieges at Calais and Reims, for some reason Edward III didn't follow his grandfather's example: he just didn't hire engineers.
In response to the power of mines and trebuchets, walls, even town walls, were built much thicker than before. So in practice all the towns you'd really want to break the walls of were trebuchet-proof.
Towns have enough people and building materials within them that they could build the walls back up nearly as fast as the besiegers knocked them down.
Trebuchets are vulnerable to counterfire, and mines to countermining. Perhaps French townsmen were just much better at siege defense than we might imagine.
Despite being quick to adopt some other military innovations, Western Europeans never really took to siegecraft seriously until cannon came along. For some reason, cannon were appealing from the start in a way the other approaches weren't.
Are any or all of these part of the answer? Is there something else that explains it?
EDIT: the right answer may be "food!" Quoting Jonathan Sumption's Hundred Years War, volume 3:
Sieges posed special difficulties of supply. A siege army was rooted to the spot, its foragers forced to look for supplies over ever greater distances the longer the siege lasted. This was one reason why the English rarely attempted them...
Unlike the English, though, the French could bring supplies overland through friendly country from considerable distances, especially where there were navigable rivers.
In other words, the English could only conveniently besiege places like Calais or Harfleur, ports close to the English Channel and England's own food supplies. Elsewhere in France, they had no way to deliver their besiegers the huge amount of food required to maintain an army sitting in a single spot. This explains why the French often mounted sieges in the Hundred Years War, and the English rarely.
And the English knew their problem going in, so they didn't bother investing in good siege equipment or personnel in the first place.
As most things do when it comes to war, the lack of successful English sieges largely came down to money. For almost the entirety of the Hundred Years War, England had almost no chance of matching the French financial contribution to the war. In many ways this is logical: France had a much larger population. In addition, England faced the additional disadvantage of pursuing a war on the other side of a large body of water, which would limit the number of men, horses and equipment that could be brought to bear against the French crown. One could argue that England was therefore only ever capable of succeeding when under an extremely capable monarch (Edward III and Henry V) and even the only in certain circumstances. I would argue that this was actually never the case. English offensive strategy thus resolved upon either bringing a French army to battle on superior terrain, or drawing them away from a siege or offensive. Both were obtained through a chevauchee , or mounted raid through the enemy's territory. This was almost always dependant upon bring English troops to a friendly port: Gascony, Calais, Brittany or Normandy and marching into France along a wide front. Oftentimes towns and cities would surrender as the English army approached (sometimes accepting a garrison) but equally as likely they opened their gates to the French army as soon as the English left. A siege in these circumstances was a poor decision as the French army (or armies) would follow the English at a close distance. The main situation where a main English army stopped to siege a fortified place was the siege of Calais, following the victorious battle of Crecy. In this case, England marshaled an extraordinary war effort, blockading the city from the sea and essentially building a city on land to sustain the siege on land. This was an incredibly expensive endeavor, needing the popularity gained from the victory at Crecy and a young, charismatic king. Similarly, the Duke of Lancaster's successes in Gascony around the same time were rarely the result of a long siege and instead came from the perceived hopelessness of resistance. The greatest extent of English territorial gains in the Southwest came not with methodical sieges, but with the treaty of Bretigny , and their subsequent conquest by the French was after years of methodical sieges by up to four armies. More decisive by far was diplomacy and the perceived helplessness of the English war effort. In the eyes of plenty of towns and cities, it was better to be on the winning side, especially if it meant increased privileges and reduced taxes. I'm typing this on the train so apologies for any typos and for the brevity, I'd be more than happy to elaborate when I get home.
It's less a matter of technology and more the effort required to bring the technology to bear against the towns.
Mining is time-consuming and requires much work and labor. Trebuchets require skilled engineers but also a mean of either building them on the spot (which is time-consuming) or transporting the equipment (which is expensive). Gunpowder weapons likewise required a steady supply of ammunition.
So it really wasn't a matter of lacking the technology - but instead lacking the logistics to actually bring these technologies to bear against the French fortified positions. And in any case many of these technologies were not exactly fool proof - Henry V's famed Agincourt campaign for instance was extremely well-funded but basically drained itself of most of its energies by the siege of Harfleur, which eventually fell due to siege artillery. This was why the army ended up undertaking an ill-supplied high-risk march across the French countryside.