Send us Fan Mail
This is the second episode of a two-part series on the evolution of castle-building and siege warfare in Britain from the Norman Conquest through the fifteenth century. My very special guest for both is Paul Remfry, a world renowned expert on castles whom Ellen and I met during a Scholarly Sojourn tour of castles associated with the Albigensian Crusade. Part one concluded with two sieges that marked the reign of King John: his loss of Richard the Lionheart's great Norman castle of Chateau Gaillard, and and his successful siege of Rochester castle in 1215 during the First Barons War. This episode begins with a less well know but equally important siege, the siege of Kenilworth Castle, from June 21 to December 13, 1266, the longest and largest siege in English history. We then turn to King Edward I's great Welsh castles, a subject on which Paul Remfry has published extensively, and to Edward I's siege of Stirling Castle in Scotland, which involved the use of massive trebuchets and even gunpowder. Paul concludes by considering the impact of gunpowder artillery on siege warfare and castle building, focusing on three siege of Harlech castle. I hope that you will join us.
(I would also want to let you know that our next episode will be a very special one: an interview with New York Times bestselling author Bernard Cornwell about historical fiction writing. I hope you will join us for that too!)
For images and details about the castles mentioned in this episode:
Wikipedia entry for "Kennilworth Castle" https://en.wikipedia.org/wiki/Kenilworth_Castle
Criccieth Castle, Wales (check out the picture of the arrow loops): https://www.castlewales.com/criccth.html
For Edward I's Welsh castles, see Paul Remfry's wepage on "The Castles of Wales" website: https://www.castlewales.com/remfry.html
For Stirling castle, see StoneKeep Atlas webpage: https://stonekeepatlas.com/castles/stirling-castle/
This episode includes a musical snippet from "Ja Nus Hons Pris" by Richard the Lionheart - Renaissance Lute - Edward Foster #medievalmusic #lute (https://www.youtube.com/watch?v=tURvt-uOnKg)
Arrow loop: https://www.castlewales.com/arrow.html
GLOSSARY OF TERMS FOR CASTLES AND SIEGE WARFARE
Arrow-slit. A vertical slit in the castle wall, used by archers. Also referred to as an arrow-loop.
Barbican. A fortified outward extension of a gateway, used to provide additional defense in depth.
Battlements are the defensive features of the parapet (i.e. the low protective wall along the outer edge of the ramparts of castle walls). The most common form is crenellation, a defensive scheme alternating low stone blocks (merlons) and openings (embrasures or crenelles) extending along and over the parapet, giving the battlement its “saw-tooth” appearance. Archers use the crenelles to shoot and then duck behind the merlons for protection.
Concentric castle. An advanced form of castle-building featuring two concentric rings of walls, in which the inner wall is usually higher than the outer. The gates are not aligned. Attackers who breach the outer wall are caught in the narrow space between the walls, exposed to archers on all sides. The earliest concentric castles are found in the Latin Crusading states of the Levant. The earliest example of a concentric castle in Britain is Dover, which became a concentric castle when outer curtain walls were added in the late twelfth century by King Henry II and by King John and King Henry III in the thirteenth century.
Curtain wall. The heavy defensive wall encircling and enclosing a courtyard (bailey) and tower (keep).
Hoarding. A wooden balcony, often temporary, built over the edge of crenellations and providing a form of machicolations. Also called a bretache.
Machicolation. A gap in the base of crenellations along a parapet, used to drop stones or other material on attackers below.
Portcullis. A heavy gate within a castle’s gateway that is raised and closed vertically by windlass or a counterweight mechanism. The portcullis typically takes the form a lattice (i.e. an open mesh) grid of wood, iron, or both, that makes it more resistant to battering rams and allows defenders within to fire arrows at the attackers. The bottom of a portcullis would have metal spikes designed to make it more difficult for attackers to lift it off the ground and which would impale a man or a horse caught beneath it. The roof over the space between the outer gate and the portcullis would be equipped with “murder holes,” through which defenders could drop stones or boiling water on attackers. A large castle might have a series of portcullises.
Trebuchet. A type of siege engine designed to throw large stone projectiles or incendiaries. A trebuchet was a giant lever, consisting of a heavy, triangular timber frame that anchors the axle and supports the entire weight of the machine under intense operational stress; a pivot beam, that is a long asymmetric wooden lever arm balanced on a central axle. The pivot point is placed close to one end, splitting the arm into a short, heavy section and a long, light section; a sling pouch, that is a rope pouch attached to the tip of the long end of the throwing arm, which acts as a double pendulum, adding velocity on release. Early trebuchets were traction devices, equipped with ropes that men pulled on to draw back the pivot beam, and then release. In the early thirteenth century, traction trebuchets were replaced with the more effective counterweight trebuchet. In a counterweight trebuchet propulsion is provided by a counterweight, a massive basket at the short end of the pivot beam filled with rocks. rubble. and melted lead. For maximum range, the counterweight needed to be one hundred times the weight of the projective. The counterweight of a large trebuchet would be ten to fifteen tons. The largest counterweight trebuchets could throw stone projectiles weighing 100-300 pounds a distance of up to 300-350 yards. The adoption of the counterweight trebuchet was a gamechanger in medieval siege warfare.
DEVELOPMENT IN GUNPOWDER ARTILLERY IN LATE MIDDLE AGES
Technical innovations:
POWDER MILL. Bt 1400 recipes of gunpowder close to ideal proportions of saltpetere (75%), sulphur (12%), and charcoal (13%) came into use, though by 1450 most powder makers preferred less efficient mixtures. The reason why was a new technique of powder making that made powder far more powerful. By 1400/1420 powder was beginning to be ‘engrained’ or ‘corned’: mixed together when wet and alowed to dry into kernels. New ‘corned powder-grains’ no longer disintegrated into components (sulphur, saltpetre and charcoal), so could be prepared in advance. (Before this powder had to be mixed on the field.) Corned powder was also more efficient, because the burning between powder grains permitted a more rapid transformation of the solid into gas.
Advances in FOUNDING cannon (bronze, brass, sometimes iron). In 14th century cannons were made by beating together strips of forged iron. The result was that such cannons often exploded. By early 15th century cannons were made along the same lines as bells (and by bell-founders), by founding iron, pouring it in molten form into moulds and then boring with a steel tipped drill to insure regularity of the bore
METALLURGICAL INNOVATION: new process of iron smelting made the production of iron less expensive (addition of limestone ‘to the flux during the ore refinement process increased temps necessary so that iron could only be smelted in blast forges, invented c.1340, but changed structure of slag from 2FeO.SiO2 to CaO.SiO2. This meant increased output as less atoms of iron were wasted from each molecule of slag.
LONGER BARRELS. Barrels were lengthened. 1400 ratio of barrel length to diameter of ball was about 1.5:1. By 1430 it was 3:1. Result was to increase accuracy and velocity of shot because it increased amount of time over which pressure of the exploding gunpowder accelerated shot. Kinetic energy is function of square of velocity, so major increase in effectiveness of guns.
RATE OF FIRE This also permitted more rapid firing. In early 15th cent loading a gun was elaborate process involving three chambers to allow the building up of pressure: needed to fill rear three fifths of chamber with powder. Next fifth left empty, and last fifth filled by wood plug fitted into barrel with soft wood wedges. This was covered with mud and straw and allowed to dry. The powder would then be ignited and pressure would build up until the plug popped out like a champagne cork. Rogers 268: ‘This elaborate procedure so slowed down the firing process that one master gunner, who achieved the remarkable feat of firing his bombard three times in a single day and hitting different targets each time, was forced to make a pilgrimage from Metz to Rome, because it was thought he ‘could only have been in league with the devil’. Maximum rate of fire: 6-8 shot from short barreled bombards.
By late 15th century switch to tight fitting caliber iron shot allowed movement away from separate chambers and plugs.
TRANSPORT: In mid 15th centu
Listen on Podurama https://podurama.com
Intro and exit music are by Alexander Nakarada
If you have questions, feel free to contact me at [email protected]
