Fortifications are structures built by human beings for the purpose of warding off attacks by hostile animals or humans.

Fortifications are structures built by human beings for the purpose of warding off attacks by hostile animals or humans. In the broadest sense, fortifications can be forms of protection, such as armor, inoculation, or even insect repellent, worn by an individual to protect against harm. Fortifications can also be communal defenses, such as forts, moats, walls, or the “strategic missile defense,” a proposed network of satellites positioned in outer space to protect against attacking ballistic missiles. In the study of warfare, “fortifications” generally refers to temporary or permanent communal defenses against attacks by human enemies. Temporary fortifications for immediate use in battles or other engagements are called “field fortifications” to distinguish them from permanent structures such as castles, stone walls, and forts.Fortifications;ancientFortifications;ancient

In Stone Age;fortificationsNeolithic times, small villages were located either on high ground or in barely accessible areas reached only with considerable difficulty. Where nature did not provide a barrier to intruders, human ingenuity placed TrenchesPalisadestrenches, palisades, or Moatsmoats over which bridges could be placed or removed. These three types of defenses, when intended to protect against other humans, were the first military fortifications.

It seems likely that permanent fortifications evolved in response to the settling of agricultural communities. Early fortifications did not require much sophistication, because threats came mainly from weak and desperate nomadic individuals or from small raiding parties. Jericho (city);fortification ofJericho–an agricultural community in the Jordan Valley north of the Dead Sea, settled in part because of its celebrated spring, which provides a thousand gallons of water every minute–is believed to have been the first town to build an encircling fortification, around the fifth millennium b.c.e. The town was surrounded by a stone circle and a massive tower, also of stone, that enabled lookouts to spot potential enemies long before they arrived. It is not currently known whether there were such fortifications in the Old Kingdom of Egypt, though fortifications on a large scale would certainly have required an advanced degree of political organization.

In an era when the principal weapons were spears, swords, and arrows, permanent fortifications were an effective defense against swift and vigorous frontal attack. The safest and most effective means of conquest was by Siege warfaresiege: an attack on or blockade of a city or castle, in which the inhabitants would be starved, frightened, or bored into submission. The Trojan War Trojan War (c. 1200-1100 b.c.e.)(c. 1200-1100 b.c.e.) was basically a ten-year siege of Troy by the Greeks. Legend indicates that even after such a long period of time, Troy would not have fallen but for the Greece;siege warfareGreek stratagem of the Trojan Trojan horsehorse. The Trojan horse was a large, hollow, wooden horse placed outside the Trojan gates. The Trojans were deceived into tearing down their own gates so that the horse, and the Greeks hidden within it, could enter.

The difficulty of a successful siege lay in maintaining an army in the field for a sustained length of time. Without regular supplies, the army laying siege would be compelled to withdraw, especially if the besieged party had, as in the case of Jericho, access to water and food. Even if the fortification could hold out, a siege might end if there were a betrayal, stirred by civil strife or bribery.

Assyrian Assyrians;fortificationsreliefs show that by 850 b.c.e., the principles of fortress building were already in place. Portrayals of military camps of the period show them as round and reveal curtain walls, or protective walls between gates or bastions; loopholes, small holes for shooting arrows; parapets, guarding walls at the edge or terraces of a building; crenelation, or repeated depressed openings; strong, fortified gates; and Towerstowers or bastions, projections from the curtain walls. With all these defenses, no part of the wall went unobserved or undefended. As more and more of the world became civilized, city walls became regular parts of landscapes. Rare was the city, such as Sparta or Rome;sieges ofRome for a good part of its history, that could boast of its security with an absence of walls. It was a glaring indication of Rome’s decline when, in the third century c.e., Aurelian (Roman emperor)Aurelian built new Walls;as fortifications[fortifications]walls for the imperial capital. When siege equipment, such as battering rams and catapults, came into use in the West, walls were thickened and made higher, and deeper moats were dug to provide further protection. Eventually, as better organization and more money became available, empires were able to construct monumental fortifications such as the Great Wall of Great Wall of ChinaChina, built in the third century b.c.e. during the Qin (Ch’in) Qin DynastyDynasty (221-206 b.c.e.) and Hadrian’s Hadrian’s Wall[Hadrians Wall]Wall in northern England, built on the orders of the Roman emperor Hadrian around 122-136 c.e. These fortifications were the greatest military structures of the ancient world.

Egypt Africa;ancient fortificationsEgypt;fortifications inis a land blessed with natural defenses. To the west of the Nile Valley lies the immense Libyan Desert, to the east, the Arabian Desert. To the south are the high rocky ledges of the Nile River cataracts and, to the north, the Mediterranean Sea. Beyond the cataracts to the south was Nubia;fortificationsNubia, a land inhospitable to agriculture but valuable for its copper, gold, semiprecious stones, and exotic animals. Here, during the Middle Kingdom (c. 2000 b.c.e.), Egypt set up a system of forts to protect its conquests of Nubia. These fortifications stretched for 250 miles between the first and fourth cataracts and gave protection to the settled areas of both river and desert. They were constructed close enough to one another that communication by fire or smoke signals was possible. The first forts, in Lower Nubia, close to the first cataract, seem to have been planned to support the agricultural communities living along the banks of the Nile; the later forts, in less civilized areas to the south, probably were established to serve as a military line marking the southern frontier of Egypt. Garrisons were maintained to administer, rule, and protect the populations, and perhaps also to intimidate them into continued submission to the central authority.

Sumeria, Asia;ancient fortificationsSumerians;fortificationsthe world’s oldest known civilization, was located in southern Mesopotamia;fortificationsMesopotamia, the fertile land between the Tigris and Euphrates Rivers. The Sumerians created walled communities at the foothills of the Mesopotamian alluvial plain. By about 3000 b.c.e., the Sumerians were building independent cities, among which Ur, Uruk, and Kish were the most prominent. These cities did not at first have walls, perhaps suggesting an absence of warfare. However, peace did not last, and between 3100 and 2300 b.c.e., war seems to have been a regular part of life and death. By 2700 b.c.e., the city of Uruk (Sumerian city)Uruk had erected walls of about 5 miles in length. The Akkadian king Sargon the GreatSargon the Great (Akkadian king)Sargon (c. 2334-2279 b.c.e.), one of the first great Mesopotamian leaders, conquered Sumeria and upper Mesopotamia and may have organized the various fortified communities he encountered into an interconnected whole. Rock sculptures depicting Sargon’s grandson Naram-SinNaram-Sin (Akkadian king)[Naram Sin]Naram-Sin (c. 2261-2224 b.c.e.) seem to show well-defined fortifications, as well as some of the methods of siegecraft, particularly the breaching and scaling of city walls.

The Great Wall of China, which traverses a distance of 4,160 kilometers and is the largest defensive barrier in the history of humankind, was built to defend China against Mongol invaders.

(Mark Harris/Getty Images)

The ancient Mesopotamian city of Babylon;fortificationsBabylon, capital of the Babylonian Empire first established in the early eighteenth century b.c.e., serves as an excellent example of a city well fortified for defense. The ancient account by the historian HerodotusHerodotus (Greek historian)Herodotus (c. 484-424 b.c.e.) tells of a wall 15 miles long, 85 feet thick, and 335 feet high, surrounded by a broad, deep moat. Queen Nitocris, QueenNitocris, QueenNitocris, he adds, altered the straight-flowing Euphrates so that boats sailing to Babylon would pass the city three times before flowing through a tunnel under the wall and into the city itself. The same queen diverted the river and excavated a huge lake in order to slow the river’s course, again giving Babylonians time to prepare a defense. The Persian king Cyrus the Cyrus the GreatCyrus the Great (king of Persia)Great (c. 601-590 to c. 530 b.c.e.) conquered the city by diverting the river from its course and then marching his soldiers over the drained riverbed and through the wall. A generation later, around 520 b.c.e., when Babylon rebelled against the Persian king Darius I the Darius I the GreatDarius I the Great (king of Persia)[Darius 01]Great (550-486 b.c.e.) and appeared likely to withstand a protracted siege, the city was taken by trickery, when one of Darius’s men, pretending to be a defector to Babylon, opened the gates to the Persia;siege of BabylonPersians.

The walls of Babylon required immense size to resist siege engines, battering rams, scaling ladders, siege towers, and catapults. Powerful battering Battering ramsrams are depicted in a Mesopotamian palace relief sculpture dated to 883-859 b.c.e. A mobile siege Siege towersTowerstower has been dated to 745-727. The biblical book of Chronicles speaks of King UziahUziah (biblical king)Uziah’s stone-throwing machines, which protected Jerusalem, although most historians believe this reference to be an anachronism inserted by a later writer. These sorts of weapons did not come into widespread use in Europe until the fourth century b.c.e.

Fortified cities appeared later in China;fortificationsChina than in Egypt, sometime during the Shang Shang DynastyDynasty (c. 1523-1027 b.c.e.). Because the land did not provide trees, earthen walls were used there instead. The Great Great Wall of ChinaWall, perhaps the world’s most famous fortification, was made by connecting many small, local walls that had been constructed previously by regional rulers. The line of the wall kept changing until, by the third century b.c.e., it lay on the border between the agricultural areas, where irrigation was possible, and the unsettled pastoral lands, where nomadic life predominated. The line of the wall varied as it moved north to enclose the Ordos plateau or extended toward the west to the Tibetan plateau. The wall was relocated as changes in climate, landscape, and population caused shifts in the frontier between civilized and uncivilized regions. In the end, the length of the wall, with all its extensions and branches, was nearly 4,000 miles.

The wall’s purpose is ambiguous: It may have been principally to keep the population in or to keep marauders out. Only a wealthy and powerful bureaucracy could have afforded to build and maintain such a structure. Only a well-organized army would have dared to oppose it. That China did not rely on the wall for its sole defense is clear from the fact that the Chinese never tore down the walls around the cities where irrigated farming communities had developed. Yet the wall must have intimidated any nomads contemplating attacks upon the awesome might of the wall’s builder.

The Europe;fortificationsearliest defensive structures in Europe seem to have been built in about 2200 b.c.e. in Britain;fortificationsBritain, perhaps as early agricultural communities began to wage war with one another for resources or political power. In Dorset, a gate with massive timber posts 5 feet across has been dated from this time.

The remains of a Roman fort along Hadrian’s Wall, showing a valuted underground room, in Northumbria, England.

(AP/Wide World Photos)

The Greece;fortificationsGreek city-states that developed during the barbarous period known as the Greek Dark Age (about 1100-900 b.c.e.) at first fortified only an Acropolisesacropolis, a citadel located on a hill used as a refuge in times of war. Poverty was surely the reason for the limited defense; walls were expensive, and a sparsely populated agricultural society would not have been able to afford them. In the flush of success after the Greco-Persian Greco-Persian Wars (499-448 b.c.e.)[Greco Persian Wars]Wars, however, the Athenian general and statesman Themistocles (c. 524-c. 460 b.c.e.) persuaded his fellow Athens;fortificationsAthenians to rebuild the city’s walls and its harbor, known as the Piraeus (Athens)Piraeus. About three decades later, his successor, PericlesPericlesPericles (c. 495-429 b.c.e.), persuaded them to build the Long Long Walls (Athens)Walls between Athens and the harbor, so that even during a long siege the city would have access to supplies from the sea. Battles in Greece traditionally had been fought outside the cities. However, during the Peloponnesian Peloponnesian War (431-404 b.c.e.)Wars (431-404 b.c.e.) and increasingly throughout the fourth century b.c.e., cities themselves were targeted directly. Throughout the Hellenic world, cities used their wealth to expand their fortifications, so that by the third century b.c.e., places such as Rhodes and Pergamum had fortresses as strong as any found in later times. These fortresses possessed multiple walls that provided mutual cover, so that if the exterior walls were scaled by invading enemies, the enemies would find themselves trapped between the scaled exterior wall and additional interior walls.

Hadrian’s Wall in Roman
Britain, c. 122-136 c.e.

The account by ancient Greek historian ThucydidesThucydides (Greek historian)Thucydides (c. 459-402 b.c.e.) of the Spartan siege of Plataea, Siege of (429-427 b.c.e.)Plataea (429-427 b.c.e.) is perhaps the most revealing ancient account of siege warfare before the adoption in Greece of sophisticated siege engines. It also illustrates the use of field fortifications. While the Plataeans themselves were enclosed behind their walls, the Spartans worked continuously for seventy days to put up a Palisadespalisade, or fence of stakes, made from fruit trees. They added timber and laid it in a lattice to support a mound of wood, earth, and stones. For their part, the Plataeans built up their wall opposite the mound to a great height, protecting it with hides against hostile burning arrows. In addition, they pulled down part of the wall where the Spartan mound abutted so that they could carry its dirt into their city, thus forestalling the mound’s growth. The Sparta;siege warfareSpartans took the countermeasure of twisting clay in wattles of reeds to prevent the soil from being carried away, and the Plataeans responded by digging a tunnel under their wall to the mound and using it to carry away more mound material. The Plataeans also built a crescent wall inside their outer wall, so that if the first wall were taken, the enemy would have to begin anew with a fresh mound. When some simple siege engines and an attempt to burn the city also failed, the Spartans built a wall, or Circumvallationcircumvallation, around Plataea and left a small force to continue the siege. After two years, the Plataeans ran out of provisions and surrendered to the Spartans, who killed them all.

Macedonian conqueror Alexander the Alexander the GreatAlexander the Great;siege warfareGreat (356-323 b.c.e.) conducted at least twenty sieges during his conquests, succeeding under the most difficult of circumstances. His 332 b.c.e. victory at Tyre, Siege of (332 b.c.e.)Tyre, an island fortress that he attacked by means of a mole constructed from the shore to the island, and that against Prince Ariamazes of Sogdiana, whose mountain fortress Alexander captured in 328 b.c.e. by means of mountaineers from above, are perhaps his most splendid triumphs over seemingly insurmountable fortifications.

In Roman mythology, Romulus and Romulus and RemusRemus, the twin sons of Mars, the Roman god of war, founded the city of Rome;fortificationsRome. After a quarrel, Romulus supposedly killed Remus and built walls around the city. However, whatever walls Rome may have had in its early period were insufficient to keep out the Celts;sack of Rome[Rome]Celts, who sacked the city in 390 b.c.e. Although this attack may have had a psychological impact on the city of Rome, it seems to have had no major political results. A few years later, the Romans built a massive wall, parts of which still stand. As Rome grew, however, it gave up its walls, so proud of its might and its policy of offensive Preemptive warfare;Romepreemptive strikes against enemies that it felt no need to fortify the city. During the Empire, Rome rarely faced enemies capable of organizing the siegecraft and supplies that would allow them to undertake long sieges against the well-stocked Roman garrisons. The would-be challengers functioned at little more than a tribal level and could not afford fortifications that would have been able to withstand the imperial army.

Toward the end of the third century c.e., Emperor AurelianAurelian (Roman emperor)Aurelian (c. 215-275) fortified Rome with a wall 12 miles around and 40 feet high, a structure that no doubt protected the citizens against the increasingly frequent barbarian forays into Roman territory, but the perceived need of which foreshadowed the precarious state of the Roman Empire. Cities in Gaul;fortificationsGaul and Spain;fortificationsSpain were also fortified with walls from this time, though at a fairly slow pace. Rome accelerated its building of chains of forts along the North Sea and Atlantic coasts, but when these frontier defenses were overcome by the Huns;fortifications againstHuns, the empire lay vulnerable.

To maintain their empire, the Romans built a system of forts, first in open territory, for the purpose of controlling the surrounding countryside, and later on hilltops where there were extensive views for keeping watch. It is likely that a coherent imperial policy dictated a standard form of forts and their distances from one another. In general, Rome used a cordon system of forts and watchtowers without running barriers.

It is believed that a Roman army on the march erected a temporary camp every night. As part of their individual equipment, soldiers carried stakes with which to construct a palisade on top of a bank of earth, which was made by digging a ditch around the camp and piling the earth on the inside perimeter. Although Flavius Vegetius Vegetius Renatus, FlaviusVegetius Renatus, FlaviusRenatus, a late fourth century c.e. Roman military theorist, lamented in his time the fact that soldiers no longer carried the tools or were trained to construct such camps, by Vegetius’s time, Rome’s military was used primarily for defense and its system of permanent forts was already in place.

The principal weapons used in the Maya;fortificationsMayan lowlands, which were populated as early as 1000 b.c.e., seem to have been spears, though clubs and knives were also used. Because these weapons did not pose the same dangers as did arrows or other projectiles, Mesoamerican Mesoamerica;fortificationsfortifications did not need overlapping fields of vision. Thus, walls projecting outward from the main fortress–an identifying characteristic of forts in Europe and Asia–were unnecessary. As a result, it is at times difficult to identify certain archaeological sites as fortifications. What appear from the bottom of a mountain looking upward to be walled fortifications may appear from above to be terraced retaining walls. One might wonder whether the appearance as a fortification was designed to discourage would-be attackers or merely was a result of construction methods and topology. Although these questions cannot be answered, freestanding walls with Moats;Mayanmoats in front of them do suggest strongly that these structures were fortifications. The fighting among early American peoples was intense and continuous, and its aim seems to have been, not the death, but the capture of the enemy for sacrificial purposes.

Before 600 b.c.e., there do not seem to have been major permanent fortifications, but, from 600 to 300 b.c.e., as dispersed settlements were replaced by larger societies, more hilltop sites were constructed. Lowland fortifications, generally embankments surrounded by ditches, seem not to have been very intimidating structures, but perhaps were adequate to the military requirements of those early periods. Inhabitants of Mexico’s Valley of Fortifications;MexicoOaxaca, fortifications inOaxaca developed probably the most complex Mesoamerican culture in the centuries before the Christian era. Its religious center, Monte Monte AlbánAlbán, rose on a series of hills. Monte Albán was fortified around 200 b.c.e. with an earthen wall of 1.8 miles, a height of between 10 and 13 feet,

and a width at its greatest of 60 feet. A large reservoir was also built that could hold enough water to sustain a siege of several years. In short, it was a structure that was as well suited for its purposes as some of the contemporaneous fortresses elsewhere in the world.Fortifications;ancient

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• Arms in Action: Castles and Sieges. Documentary. History Channel, 1999.
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Medieval Fortifications

Modern Fortifications

Sieges and Siegecraft: Ancient and Medieval