I’ve made some references to the changing nature of warfare in the 14th and 15th centuries, which it’s worth spelling out in more detail. Gunpowder changed the nature of war by changing siege strategy; whole cities could be besieged and blockaded, but houses alone were now too small.
Simple exploding powder was known in the late 1200s, but nobody began to develop it until the 1300s. Even then, it was used to set fire to buildings inside a siege, or to blow up castle walls. Its use as a directed propellant didn’t begin until the 15th century.
Early gunpowder was made from charcoal, sulfur and saltpeter. “Saltpeter” was a “salt” that grew on the “petros,” that is, stone walls. Its best growing conditions were the stone walls of an outhouse or stable, where there was a lot of urine evaporating. Later, Germans learned to use dung, urine and rock to grow it on purpose; hence its first commercial manufacture. Sulfur and charcoal were common ingredients, but gunpowder needed very fine charcoal, probably made from willow or grapevines.
The first artillery use of gunpowder may have been around 1327; “pots de fer” may have been iron pots that controlled the explosion to force a missile in just one direction. By 1346, at the Battle of Crecy, the English had three simple cannons on the hill. These early guns were small; they were iron tubes fixed to a wooden frame. But cannon use was too compelling for it not to develop quickly; we have Chaucer referring to guns and pellets in 1384.
The first obvious use for cannons was breaking a siege by pounding the castle wall more effectively than a battering ram. Metalsmiths had to figure out how to strengthen iron or copper tubes to where they could withstand an internal explosion without shattering. Iron bars, heated and twisted around the tubes, helped. But early “bombards” were always dangerous, since they could burst at any time and kill those standing nearby. They were also heavy, requiring teams of 12 and more horses to pull them into place in the field.
By the 15th century, breaking sieges was just a matter of casting a large enough cannon. Constantinople fell to a huge cannon, the biggest of its time. Walls that used to require six months to batter now fell in two weeks. So people stopped relying on walls. Fighting men needed to meet an invading army in the field and stop it from dragging its artillery up to the city or castle walls. As before, in the pre-castle days, battles were fought in a day, on a field, by men with hand-held weapons. Artillery could be used in the field, too. Armor mattered less, and lifetime training ceased to be a protection. A year’s apprenticeship to a gunpowder maker was a better life preparation than ten years of tilting and jousting. The entire structure of chivalry, including its residential strongholds, became pointless.