The Alienage
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Siege Warfare

Siege Warfare

Historical References on Medieval Europe

Contamine, Philippe. War in the Middle Ages. New York: Basil Blackwell, 1989

By a dialectical process which may be found in all periods, progress in the art of siege was answered by progress in the art of fortification, and vice versa; thus simply for purposes of exposition, methods of attack and defense will be treated separately here.

    Methods of Attack

  • "In order to capture a place recourse was often necessary to psychological or political means — a mixture of threats and clemency."
  • "A promise to respect lives and property, to allow the garrison to come out freely, or the prospect of a general massacre, arson and systematic pillaging, frequently resulted in a negotiated capitulation by the besieged. The same result might be gained by blockade, scarcity of food, poisoning water supplies and the eventual spread of epidemics."
  • "After indirect means came direct attacks. The aim of the besieger, normally superior in numbers to the besieged, being to enter the place, it was first of all necessary for him to surmount excavated defenses, dry ditches or moats filled with water. Hence the need to fill them with whatever materials were available, wood, stone, earth and so on."
  • "If the besieged were able to defend themselves, it was necessary to protect the besiegers, either while they blockaded the place, carried out approach works or mounted an attack. Hence the digging of trenches, construction of banks and palisades and, above all, the use of approach engines, various types of counter-fortifications which allowed them to continue to injure the enemy while coming up to the walls. These tower machines, belfries or wooden castles, often depicted in manuscript illuminations, bore many names, some of which had been handed down from Antiquity or had been rediscovered in specialist Latin works: sows (truies), pent-houses (vinae), cats (chattes), weasels (belettes), sentry-boxes (guerites), covered ways, cats' castles. Sheltering archers, knights and crossbowmen, the majority of these engines could be placed on wheels or rollers to be pushed close to the opposing walls by the efforts of dozens and dozens of laborers. Smaller ones were erected on carts."
  • "There were other weapons to break down, pierce, shake or rip open the walls. Sometimes simple picks and iron bars were used; sometimes battering rams. The same effect could be achieved using stone throwing machines called trébuchets, petrariae, mangonels and 'chaables'."
  • "The period 1180-1220 witnessed great advances in this domain thanks to the use of machines worked by balances and not only by human traction — the most rudimentary form — but by fixed or mobile counterweights."
  • "Trébuchet artillery did not simply aim to demolish or shake fortifications. It was also used to throw incendiary projectiles and to introduce epidemics into a besieged place by throwing the carcasses of putrefying animals."
  • "Sapping and mining were frequently practiced. An instance of this may be found, for example, at the time of the siege of Château-Gaillard. If a large enough breach had not been made, an attack could be mounted with scaling ladders."
  • "Of course none of these various methods was unknown before 1150. Even the mangonel is mentioned by Abbo at the time of the siege of Paris by the Vikings in 885… It seems nevertheless that engines and war-machines were used much more frequently in the twelfth and thirteenth centuries and that various technical improvements permitted more rapid and accurate firing of heavier missiles. At the same time sapping works became more sophisticated and effective."
  • "All this is accounted for by the more frequently attested presence in the sources of technical personnel, miners, pioneers and specialist craftsmen. Among these people a little group, particularly from the end of the twelfth century, began to stand out: masters of the engines or engineers, who benefited from financial advantages which underline the price people were prepared to pay for their services."

    Methods of defense

  • "When besieged, a castle, garrison or town had a number of possible means of counter-attack. It could wait for or seek the intervention of a relieving force which would place the besiegers in an uncomfortable position, forcing them to decamp. Sorties could be made to break up the blockade or spread panic. They could hope for climatic or monetary difficulties, lack of foodstuffs and discomfort, desertion and disease, to break up the siege. To the trenches of the besiegers they could respond with their own counter-mines. Towns and castles could use trébuchets and stone-throwers just as easily as their besiegers… The presence in opposing camps of trébuchets led to proper artillery duels, the primary objective of the protagonists being to destroy the enemy engines."
  • "Because of their multiple functions, to which their military purpose was in general subordinated or added later, towns possessing a system of fortifications often presented many weak points. Alongside a few cities which fully utilized the military potential of their site (on a spur or plateau, in a marsh or surrounded by water courses), there were many others which had spread out, thinking only about convenience for roads and building."
  • "Even when they existed (and many towns still lacked walls), urban fortifications were often very primitive, additionally weakened by openings and posterns which gradually multiplied. On the exterior of the ramparts, houses, barns, mills and orchards rendered defense more difficult by permitting potential attackers to approach under cover. The first concern of a threatened town was thus to block up the greatest possible number of openings and to clear the terrain around the enceinte in order to allow rapid circulation by the defenders either at the foot of the walls or on wall-walks (chemins de ronde). At the same time platforms, palisades, coursières and vaulted passages were repaired or built. Gates were the object of special attention. The majority were not only blocked up and flanking towers filled with men and materials but they were provided with foreworks, barriers and barbicans."
  • "Examples furnished by the first register of Philip Augustus concerning the walls of Laon, Compiègne, Saint-Mard-en-Soissonnais, Melun and so on show that it was considered normal at the beginning of the thirteenth century for ditches to be between 8 and 11 m deep and 12 and 19 m wide, curtains to be between 6 and 10 m high to the base of the parapet, and at the level of the chemins de ronde between 1.20 and 2.10 m wide. The same specifications envisaged gates flanked by small towers with thicker walls. Some of these gates are described as simple, others as double. They were preceded by drawbridges (pontes tornatiles) whilst other small towers at variable intervals were dotted along the walls."
  • "In these circumstances one might think that to fortify a town was a long-term project allowing room for little improvisation. But in reality things were somewhat different; in emergencies, towns were capable, thanks to their human resources, of erecting in a few months summary but effective protection."
  • "Among the developments that occurred after 1150 was the increasingly frequent and systematic use of stone instead of wood, even in regions where wood remained preponderant in ordinary rural and urban buildings. This triumph of stone, which was more resistant, less perishable, more difficult to burn, was nevertheless fairly slow."
  • "At the same time knowledge of merlons, hourds (soon replaced by machicolations), coursières, brattices, barbicans and drawbridges was increasingly disseminated. Archer-loops became more numerous and better placed; recourse to the crossbow allowed a more systematic flanking fire. To obstruct assault by scaling ladders, the curtain walls were raised… To counter sapping, the base of the walls were reinforced and thickened and the scarps of ditches were paved with stone."

Jones, Archer. The Art of War in the Western World . Oxford: Oxford University Press, 1987

"William's French castle was similar to the model used throughout Europe. Because attackers might well first assail the weaker palisade, whose fall would not effect the defensive strength of the structure on the mound, this elementary castle embodied, to a modest degree, the principle of successive lines of defense. But the simple design provided no opportunities for flanking fire. The stone castle, which in the eleventh century began to supersede the wooden, included these two fundamental principles while adhering to the basic model developed for the wooden castle. A powerful stone tower with a walled stone enclosure, which embodied smaller towers for flanking fire and in more elaborate castles two complete concentric lines of walls, meant a structure with as many as three lines of resistance — outer walls, inner walls, and main tower. Town fortifications that began as wood also progressed to stone, incorporating the same principles as ancient town walls. Usually towns has a castle or citadel, which served as a place of final defense and as a stronghold from which the ruler could dominate the town."

"Medieval soldiers used all the ancient devices except the Roman agger."

"Until the beginning of the twelfth century, the only known kinds of artillery were catapults worked by torsion and tension. A torsion catapult used a heavy timber frame with a mass of twisted rope strung across near the front. In this twisted rope the builder secured one end of a moveable beam having a spoon shaped hollow in its other end. Operators pulled this free end backward and down by a large winch at the rear of the frame, against the resistance of the twisted ropes, and placed the stone to be thrown in the spoon-shaped cavity. They then released the free end of the moveable beam by releasing a catch. The force of the twisted ropes then made the beam describe an upward and forward curve, moving fast enough to flip off the stone at a high angle of elevation. Such a catapult was known as a mangon, mangonel, or sling. Of course the projectiles were seldom uniform in weight, and weather affected the ropes. Accordingly, the shots of this type of machine dispersed so widely that it was generally used for bombarding large objectives, such as towns or castles."

"A tension catapult, usually known as a ballista, consisted of an exaggerated bow wound up by winches. It shot bolts or enormous arrows with great force, flat trajectory, and considerable accuracy. Although they could not penetrate walls, they were used by besiegers and besieged against small, fairly distant objectives, such as men out of range of infantry weapons."

"In making good their approach, besiegers protected themselves against the plunging for of the defenders behind mantlets, screens strong enough to resist arrows but light enough to move easily. Besiegers might roll up moveable towers, as high as or higher than the defenses, until the towers could drop drawbridges on the battlements."

"The defects of the moveable tower are obvious. It was not only heavy but top-heavy. Accordingly, it could move forward only over ground that was smooth, level, and particularly firm. It needed protection against combustibles; rawhides were generally used in front and to some extent upon its sides. Defenders shot at it with carrying balls of burning tow."

"It was a little easier to move forward some sort of low shelter that would protect men working against the base of the defenders' walls. These shelters were fairly long, so that their occupants might come and go by the rear end (which could not be too close under the wall), and narrow and steep-roofed in proportion to their length so that they could resist stones and heavy weights dropped from above. For greater strength, the roof had a steep point and was protected against fire by rawhides."

"Either the shelter was brought within a few feet of the wall, which workmen then attacked with a ram or borer, or its head was pushed up against a wall to give cover to men attacking the masonry with pickaxes, hammers, and crowbars. The ram and borer both consisted of great beams, the largest that the besiegers could find, swung by chains from the ridgepole of the shelter. The ram had a broad solid head (like the forehead and horns of a true ram), which it butted against the wall; the borer has a pointed head, intended to break down the opposing masonry stone by stone."

"Meanwhile, the defenders, even if they failed to smash or burn the shelter from above, might grip the head of the ram or borer with large pincers to prevent the crew from pulling back for a forward stroke or might try to deaden its blows by means of rope pads or sacks thickly stuffed with soft material with which they would cover the face of the wall at the point where the blows were falling. If pincers or padding succeeded, the attackers had no alternative but to advance the shelter and sap the base of the wall with hand tools."

"The mine provided attackers with another resource. Starting from a sheltered position near the wall, the besiegers dug deep and then under the wall. As the mine gallery advanced under the wall, the miners shored it up with lumber. When they judged they had dug enough, they burned the timber, collapsing their mine; if they had made a large enough hole, a section of the wall would come down, leaving a breach."

"Fortresses were seldom taken in regular sieges as no one had the resources to sustain the necessary men… The military axiom still held that any fortress, however strong, must fall if besieged by numbers sufficient to blockade it and carry on an active regular siege at the same time… But in practice medieval fortifications rarely fell in this way."

"The problem of supplies, however, also limited besiegers. It proved to be a difficult task to sustain an attacking force and, often, because of the limited term that feudal forces had to serve, to keep the besieging army together long enough for the defenders to exhaust their food reserve. The strength of castles and fortified towns remained a fundamental tactical and strategic factor in medieval warfare."

Nicolle, David. Medieval Warfare Source Book Warfare in Western Christendom. London: Brockhampton Press, 1999

"Defense remained largely passive throughout the early medieval period, with little attempt being made to engage the besiegers in an effective manner. Only by making sorties and fighting against direct assault did the defenders normally come into physical contact with their attackers."

"There are plenty of references to stone-throwing machines of presumably late Roman type being used in Carolingian siege warfare. These were generally aimed at gates rather than walls. Scaling ladders and rope ladders, the testudo moveable wooden shed or perhaps infantry protection of interlocking shields, as well as battering rams were all employed."

"During the second half of the 9th century simple versions of the man-powered, beam-sling mangonel were introduced into Carolingian France. At first they might have been made and even operated by Byzantium military engineers. Such simple mangonels may then have become relatively common during the next hundred years. Nevertheless, sieges were now normally on a very limited scale. Larger targets such as fortified towns posed serious problems for the small armies of the 10th and 11th centuries. Perhaps as a result, increased efforts seem to have been made to get spies into such towns to find their weak spots. Otherwise an attacking force might have to rely on a sudden assault in the hope of seizing an unsecured gate."

"More often than not, the attackers had to fall back on a prolonged blockade; operating from their own fortified camp erected nearby since they were rarely able to surround the entire fortifications of a town. Both sides now used small stone-throwing engines while the attackers might also dig trenches in order to reach the enemy wall in relative safety. Once there, they could erect various forms of wooden tower or sturdy shed from which to attack the wall itself. Meanwhile the defenders would attempt to wrench their enemies out of such wooden structures using large hooks on wooden poles."

"Developments in siege techniques were almost as dramatic as those in the design of fortifications during the 12th and 13th centuries. They were of course, related. Most importantly there was a considerable increase in the use of more powerful stone-throwing machines. But this did not mean sieges necessarily got faster or more decisive. Sieges often dragged on for a very long time, which tended to have a serious effect on the morale of the attackers; perhaps more so than the defenders."

"The preferred method of taking a fortified place was, whenever possible, a sudden expected assault in the hope of catching the garrison unawares, or even with its gates open. In any case the attackers hoped to invest the place before its garrison could be strengthened."

"Threats might be made to execute or mutilate captives the attackers might already be holding; threats all to often carried out."

"Hungry garrisons were taunted with the attackers' own food supplies, potential traitors would be bribed, water sources either diverted or polluted with corpses. One way or another it was clear that western European siege warfare often degenerated into forms of savagery rarely seen elsewhere… At the same time, however, the besiegers' own stinking camps frequently became riven with dysentery and other diseases as a result of the Europeans' habitual lack of hygiene."

"Larger fortified areas, such as towns or cities, could rarely be completely surrounded. In such cases a blockade was usually the only answer, unless the walls were attacked directly. But this latter tactic tended to be expensive in lives and was resorted to only in the most pressing circumstances. Instead, the steady wearing down of one section of wall, a tower or gate, was the standard way of conducting a lengthy siege."

"The first step was normally to try to fill the defensive ditch, so that the attackers' movable wooden siege-towers belfreys or berfriez, could approach the defenders' wall. This will also enable the sappers and miners to attack the base of the wall without having to tunnel too far… Consequently the defenders would try to destroy these wooden towers' before they reached the fortified wall. Here they could use various forms of Greek Fire which were known in western Europe. The defenders not only attempted to kill their attackers, but even to 'fish' them from the base of the wall or from their wooden towers, using long pivoted poles with hooks at the end known as crows. The attackers similarly used this device against the defenders. Meanwhile the garrison's best defense against mining beneath their walls was counter-mining."

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