Gunpowder has been around for centuries, and the Chinese were the ones who reportedly first discovered its explosive properties in the 11th century. At first it was probably used in fireworks and other more innocent endeavours, but it didn't take long for them to develop gunpowder into an effective military weapon. Over the course of several centuries, gunpowder eventually made it into the European conscience through trade routes and word-of-mouth, and by the 14th century, it was being fully employed on the field of battle, and in siege warfare.
Siege Warfare Before the Gunpowder Revolution
Throughout the medieval era, fortresses and castles became so elaborate and well constructed that they were almost impregnable to attack. Scaling ladders and battering rams were used, but were either easily countered by defenders or the terrain could not be easily surmounted by attackers. Catapults and trebuchets were also used with some success, but new defensive developments even rendered them ineffective. Most often, the attackers would initiate a siege; “the procedure of driving a castle or town into starvation to surrender.” Sieges were often effective, depending on the abundance of food available to the defenders, but were protracted, and often took over a year to achieve victory. So it is not surprising that many armies looked for a way to expedite the process of conquering an enemy fortress.
Early Cannons
At first, English sieges such as the one at Calais in 1346-47 used cannons “solely to cause panic”, but this modest beginning soon gave way to more cannons being used in sieges when attackers realized that the huge gunpowder artillery weapons were ideal for breaching enemy fortresses because the “walls of castles were easily damaged by the ballistic force of gunshot, and by the middle of the 14th century, nearly every siege was accompanied by gunpowder artillery bombardment.”
Early Attempts to Counteract Cannon Fire
It soon became obvious to castle architects and designers that modern castles stood no chance against these new weapons, because “with their tall, flat surfaces they were easy targets for guns. […]. The tall walls of medieval fortifications had been built to withstand weapons that could not inflict the continual barrage on a single area as could the new gunpowder weapons.”
Nonetheless, it would be too expensive and time-consuming to rebuild all of the fortresses in Britain, so instead many fortresses added guns as a defensive measure and in order to hit the targets close to city walls, gun ports were added to walls, after 1365, in order to aim more directly at attacking armies.
Examples of English castles/towns that used guns and gun ports are; Quarr Abbey (1365-1366), Canterbury town wall (1380), Southampton Castle (1382-1386) and the Winchester town wall (1390). They were mostly located at gates/ towers to allow flanking fire, but this flanking fire would have had limited effectiveness because “most gun ports only allowed less then a 45 degree angle of fire.”
New Architecture
Due to the general ineffectiveness of guns used as defenses, new architectural methods would need to be utilized in order to defend against cannons. Many towns responded by thickening their walls with piles of dirt, known as ramparts, which were supposed to disperse the immense cannon shock, but most times the dirt/soil “exerted a heavy pressure on the wall and frequently weakened the masonry rather then strengthening it.”
Other’s simply thickened the masonry by adding more behind the pre-existing wall, dug deeper and wider moats, or they created a sloping wall of stone on the front of their walls, or had rounded walls built, “to create glancing gunshots, rather then direct impacts on flat wall.” All of these countermeasures were effective in limiting the destructive capabilities of cannons, but were also much too expensive for most towns/cities to afford.
The English developed what they called an Artillery Tower, which was tall, and made of stone but also rounded so as to deflect a lot of artillery shots. Its purpose was to add flanking fire to a vulnerable wall or gate, and it was the preferred English fortification all the way through the 16th century.
Leon Battista Alberti & Trace Italienne
None of these additions to existing fortresses were completely effective against artillery attack, and it became obvious that new fortresses would have to be built in order to repel cannon attacks. In the 1440’s, an Italian named Leon Battista Alberti wrote De re aedificatoria, in which he outlined five requirements for castles that would be necessary to repel cannon attack.
These guidelines became so effective that they were used all over Europe well into the 19th century, and was known as trace italienne;
1) Fortification walls facing gunpowder weapons should be both short enough to easily see the ground below them, and wide enough to withstand the impact of cannonballs.
2) Artillery towers projecting at an angle beyond the walls should be added to the fortification- this would not only protect the fortification itself but also keep offensive guns at bay and cover blind spots along the fortress walls,
3) Angled bastions projecting out at regular intervals from the fortress wall should be built, giving increasing flanking cross-fire along the surface of those walls,
4) As time passed, further refinements should be added to the fortification: wide and deep ditches along the walls to keep enemy artillery at a distance and to cut down on mining with detached bastions built beyond those ditches to further impede enemy artillery attacks, and
5) Extensions should be built to these fortifications, complete with crownworks or hornworks, to protect these outside strategic areas.
These star-shaped fortresses spread throughout Europe, and well-known examples of this type of fortification in Britain include; Roxburgh castle in Scotland, as well as Sandgate Castle and Camber Castle in Britain, both of which were commissioned by Henry VIII.
Gunpowder completely revolutionized the medieval battlefield, and irreversibly changed the ways in which engineers and architects designed their buildings and fortifications.
Sources:
DeVries, Kelly. Medieval Military Technology. Peterborough, Ontario: Broadview Press Ltd., 1992.
Reid, William. Weapons through the ages. London, England: Peerage Books, 1984.
