In even the earliest and most primitive societies, the need to stave off attackers led to the construction of defensive physical structures.
In even the earliest and most primitive societies, the need to stave off attackers led to the construction of defensive physical structures. The variety of such responses naturally became ever more diverse as groups worldwide had to meet the intersecting challenges of the foe, their own resources, climatic and geographical constraints, and anticipated forms of organized violence. Fortification is thus any construction, permanent or transitory, earthen, organic, or stone, designed to shield defenders from an attacker while those defenders either await help or resist assaults themselves. Even with the rather limitless bounds of human ingenuity, fortifications nonetheless tend to fall within four somewhat interrelated categories: refuges, strongholds, fortified lines or zones, and urban walls.
All types appeared concurrently and in overlapping cycles of need and development worldwide before Europe’s medieval period. The Roman Empire had its own strategic mix of city
Hadrian’s Wall stretched for 117 kilometers across northern England, ranging in thickness from 2.3 to 3 meters and averaging a height of from 5 to 6 meters. The wall was part of the Roman strategy of defense in depth. In the absence of manned watchtowers and fortified camps to the rear, the Saxons were hardly set to use the wall to its best advantage. Even so, the wall did form, in its less than pristine state, something of a hindrance to the return of raiders northward. Northumbrian pursuers could count on it slowing marauders if those raiders tried to get their spoils through or over the fortifications.
It would appear that Offa’s
The impassability of terrain might make fortified lines not only a cost-prohibitive measure but also a rather unnecessary one. In Mesoamerica contending empires could keep invaders at bay simply by blocking well-established paths. In the absence of siege equipment and draft animals, such structures would not have needed much complexity to be effective. In Europe fortified bridges developed not only to secure lines of communication and transport but also to block the progress of Viking
The most famous and latest of all fortified lines are of course those of China. The Great
As the Germanic groups, especially the
The twelfth century attack and defense of a city wall, with numerous types of siege engines in use.
The situation differed in eighth and ninth century
These fortifications did not have to be terribly complex, because the Vikings had little in the way of siege weaponry. Nonetheless, Alfred’s administration prepared the burhs well, as is known from a document called the Burghal Hidage (c. 920), which lists them. By dividing the resources of the kingdom into units called hides, each of which was sufficient to provide one man for burh garrisons, the Anglo-Saxons assigned enough hides to each burh to assure that its walls were defended by one man for every 1.3 meters. Because some burhs had circumferences of over one mile, this meant that Viking invaders had to sense the sizable numbers of uncowed foes they left in their wake as they bypassed the burhs. The burhs themselves were formidable: The first barrier was an exterior ditch perhaps more than 30 meters wide and sometimes as deep as 8 meters; an earthen bank came next, reaching up to 3 meters in height; timber defenses surmounted this ringwork in most cases, but stone walls were put in place at major sites, especially those that housed the royal mints. Many burhs took advantage of natural defenses, such as swamps and rivers, whereas others were built upon the remains of previous Roman fortifications.
The advantages offered by burhs or even the most simple defenses naturally drew people to those fortified locales. This rationale appears to explain the growth of the stone enclosures at Great
In addition to its defensive capabilities, the motte-and-bailey had an offensive potential. As an easily built, forward base for troops, mottes were useful in subduing hostile regions. One of the earliest builders of mottes, Fulk
Although the use of timber castles continued into the thirteenth century, the transition to
The new preference for such expensive and mammoth constructions physically reflected the increasing wealth of the feudal nobility as principalities such as Anjou, Normandy, and of course, England, stabilized. The ability of these lords to command greater resources also meant they could put better-equipped armies into the field. Thus the siege weapons of antiquity, which had never completely been forgotten, began reappearing: battering rams, ballistae, onagers, and later, the trebuchet, as well as the old standby, fire. Successful defense against these weapons required the use of stone. The spread of castles was dramatic: The French province of Poitou had only three castles before the Viking incursions, but at least thirty-nine castles dotted the province by 1100. No archaeological evidence has been found of castles in the northwestern region of Maine before 900; two centuries later there were sixty-two. Other regions saw similar levels of castle-building. Such numbers do not take into account fortified residences, which lacked the defensive power of castles.
The intensified wealth and warfare of Europe did not account alone for the spread of more sophisticated defenses; inspiration came also from Constantinople and the Muslim fortresses taken only with the greatest effort during the
The most famous of the Crusader castles is Krak des
Krak des Chevaliers, in modern Syria, the most famous of the Crusader castles.
The lessons learned in the Middle East soon wrought changes in the structure of castles in Europe. Circular towers came to predominate, as castle builders realized that square angles gave attackers extra blind spots to exploit; more important, curved surfaces resisted the projectiles of pregunpowder artillery better than flat ones. King Richard
The most distinctive examples of concentric castles were Edward
Although castles would appear during
In very different circumstances, the
The techniques adopted by European cities may be highlighted by comparison with contemporary settlements in
In Europe, though, the pendulum of innovation was already swinging away from the high walls of concentric castles and cities. Gunpowder
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Sieges and Siegecraft: Ancient and Medieval