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Fortification
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Fortifications are military constructions and buildings designed for defense in warfare and military bases. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs. The term is derived from the Latin fortis ("strong") and facere ("to make").
military installations are known as forts, although they are not always fortified.
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Encyclopedia
Fortifications are military constructions and buildings designed for defense in warfare and military bases. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs. The term is derived from the Latin fortis ("strong") and facere ("to make").
Nomenclature
Many military installations are known as forts, although they are not always fortified. Larger forts may class as fortresses, smaller ones formerly often bore the name of fortalices. The word fortification can also refer to the practice of improving an area's defense with defensive works. City walls are fortifications but not necessarily called fortresses.
The art of setting out a military camp or constructing a fortification traditionally classifies as castrametation, since the time of the Roman legions. The art/science of laying siege to a fortification and of destroying it has the popular name of siegecraft and the formal name of poliorcetics. In some texts this latter term also applies to the art of building a fortification.
Fortification is usually divided into two branches, namely permanent fortification and field fortification. Permanent fortifications are erected at leisure, with all the resources that a state can supply of constructive and mechanical skill, and are built of enduring materials. Field fortifications are extemporized by troops in the field, perhaps assisted by such local labor and tools as may be procurable and with materials that do not require much preparation, such as earth, brushwood and light timber, or sandbags (see sangar). There is also an intermediate branch known as semipermanent fortification. This is employed when in the course of a campaign it becomes desirable to protect some locality with the best imitation of permanent defences that can be made in a short time, ample resources and skilled civilian labor being available.
History
Ancient
From very early history to modern times, walls have been a near necessity for every city. Uruk in ancient Sumer (Mesopotamia) is one of the world's oldest known walled cities. Before that, the city (or rather proto-city) of Jericho in what is now the West Bank had a wall surrounding it as early as the 8th millennium BC.
The Assyrians deployed large labour forces to build new palaces, temples and defensive walls.
Some settlements in the Indus Valley Civilization were also fortified. By about 3500 B.C., hundreds of small farming villages dotted the Indus floodplain. Many of these settlements had fortifications and planned streets. The stone and mud brick houses of Kot Diji were clustered behind massive stone flood dykes and defensive walls, for neighboring communities quarreled constantly about the control of prime agricultural land. Mundigak (c. 2500 B.C.) in present day south-east Afghanistan has defensive walls and square bastions of sun dried bricks.
Exceptions were few — notably, ancient Sparta and ancient Rome did not have walls for a long time, choosing to rely on their militaries for defense instead. Initially, these fortifications were simple constructions of wood and earth, which were later replaced by mixed constructions of stones piled on top of each other without mortar.
In Central Europe, the Celts built large fortified settlements known as oppida, whose walls seem partially influenced by those built in the Mediterranean. The fortifications were continuously expanded and improved.
In ancient Greece, large stone walls had been built in Mycenaean Greece, such as the ancient site of Mycenae (famous for the huge stone blocks of its 'cyclopean' walls). In classical era Greece, the city of Athens built a long set of parallel stone walls called the Long Walls that reached their guarded seaport at Piraeus.
Large tempered earth (ie. rammed earth) walls were built in ancient China since the Shang Dynasty (c. 1600-1050 BC), as the capital at ancient Ao had enormous walls built in this fashion (see siege for more info). Although stone walls were built in China during the Warring States (481-221 BC), mass conversion to stone architecture did not begin in earnest until the Tang Dynasty (618-907 AD). In terms of China's longest and most impressive fortification, the Great Wall had been built since the Qin Dynasty (221-207 BC), although its present form was mostly an engineering feat and remodeling of the Ming Dynasty (1368-1644 AD) during the 15th and 16th centuries. The large walls of Pingyao serve as one example. Likewise, the famous walls of the Forbidden City in Beijing were established in the early 15th century by the Yongle Emperor.
The Romans fortified their cities with massive, mortar-bound stone walls. The most famous of these are the largely extant Aurelian Walls of Rome and the Theodosian Walls of Constantinople, together with partial remains elsewhere. These are mostly city gates, like the Porta Nigra in Trier or Newport Arch in Lincoln.
Hadrian's Wall was built in built by the Roman Empire across the width of what is now northern England following a visit by Roman Emperor Hadrian (AD 76–138) in AD 122.
Medieval
Roman forts and hill forts were the main antecedents of castles in Europe, which emerged in the 9th century in the Carolingian Empire.
The Early Middle Ages saw the creation of some towns built around castles. These cities were only rarely protected by simple stone walls and more usually by a combination of both walls and ditches. From the 12th century AD hundreds of settlements of all sizes were founded all across Europe, which very often obtained the right of fortification soon afterwards.
The founding of urban centers was an important means of territorial expansion and many cities, especially in eastern Europe, were founded precisely for this purpose during the period of Eastern Colonisation. These cities are easy to recognise due to their regular layout and large market spaces. The fortifications of these settlements were continuously improved to reflect the current level of military development.
During the reenessence era, the Venetians raised great walls around cities threatened by the Ottoman empire. The finest examples are, among others, in Nicosia (Cyprus) and Chania (Crete), and they still stand, to this day.
Early Modern
Medieval-style fortifications were largely made obsolete by the arrival of cannons on the 14th century battlefield. Fortifications in the age of blackpowder evolved into much lower structures with greater use of ditches and earth ramparts that would absorb and disperse the energy of cannon fire. Walls exposed to direct cannon fire were very vulnerable, so were sunk into ditches fronted by earth slopes.
This placed a heavy emphasis on the geometry of the fortification to allow defensive cannonry interlocking fields of fire to cover all approaches to the lower and thus more vulnerable walls. Fortifications also extended in depth, with protected batteries for defensive cannonry, to allow them to engage attacking cannon to keep them at a distance and prevent them bearing directly on the vulnerable walls. The result was star shaped fortifications with tier upon tier of hornworks and bastions, of which Bourtange illustrated to the right is an excellent example. There are also extensive fortifications from this era in the Nordic states and in Britain, the fortifications of Berwick-upon-Tweed being a fine example.
19th Century
The arrival of explosive shells in the nineteenth century led to yet another stage in the evolution of fortification. Star forts of the cannon era did not fare well against the effects of high explosive and the intricate arrangements of bastions, flanking batteries and the carefully constructed lines of fire for the defending cannon could be rapidly disrupted by explosive shells. Worse, the large open ditches surrounding forts of this type were an integral part of the defensive scheme, as was the covered way at the edge of the counter scarp. The ditch was extremely vulnerable to bombardment with explosive shells.
In response, military engineers evolved the polygonal style of fortification. The ditch became deep and vertically sided, cut directly into the native rock or soil, laid out as a series of straight lines creating the central fortified area that gives this style of fortification its name.
Wide enough to be an impassable barrier for attacking troops, but narrow enough to be a difficult target for enemy shellfire, the ditch was swept by fire from defensive blockhouses set in the ditch as well as firing positions cut into the outer face of the ditch itself.
The profile of the fort became very low indeed, surrounded outside the ditch by a gently sloping open area so as to eliminate possible cover for enemy forces, while the fort itself provided a minimal target for enemy fire. The entrypoint became a sunken gatehouse in the inner face of the ditch, reached by a curving ramp that gave access to the gate via a rolling bridge that could be withdrawn into the gatehouse.
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