A fortification (also called a fort , fortress , fastness , or stronghold ) is a military construction designed for the defense of territories in warfare , and is used to establish rule in a region during peacetime . The term is derived from Latin fortis ("strong") and facere ("to make").
128-695: The Quadrilatero (English: Quadrilateral , for greater specificity often called the "Quadrilateral fortresses ") is the traditional name of a defensive system of the Austrian Empire in the Lombardy-Venetia region of Italy , which connected the fortresses of Peschiera , Mantua , Legnago and Verona between the Mincio , the Po , and the Adige Rivers . The name refers to the fact that on
256-430: A ravelin like angular gun platform screening one of the curtain walls which is protected from flanking fire from the towers of the main part of the fort. Another example is the fortifications of Rhodes which were frozen in 1522 so that Rhodes is the only European walled town that still shows the transition between the classical medieval fortification and the modern ones. A manual about the construction of fortification
384-482: A "shell" as opposed to "shot". By the time of the Second World War, AP shells with a bursting charge were sometimes distinguished by appending the suffix "HE". At the beginning of the war, APHE was common in anti-tank shells of 75 mm caliber and larger due to the similarity with the much larger naval armour piercing shells already in common use. As the war progressed, ordnance design evolved so that
512-536: A 1543 English mortar shell was filled with "wildfire." By the 18th century, it was known that if loaded toward the muzzle instead, the fuse could be lit by the flash through the windage between the shell and the barrel. At about this time, shells began to be employed for horizontal fire from howitzers with a small propelling charge and, in 1779, experiments demonstrated that they could be used from guns with heavier charges. The use of exploding shells from field artillery became relatively commonplace from early in
640-464: A bastion of the Bavarian city of Ingolstadt , Germany . Many of the grenades contained their original black-powder loads and igniters. Most probably the grenades were intentionally dumped in the moat of the bastion before the year 1723. An early problem was that there was no means of precisely measuring the time to detonation – reliable fuses did not yet exist, and the burning time of
768-538: A better effect. This guideline was achieved by the 1960s with the 155 mm L15 shell, developed as part of the German-British FH-70 program. The key requirement for increasing the HE content without increasing shell weight was to reduce the thickness of shell walls, which required improvements in high tensile steel. The most common shell type is high explosive , commonly referred to simply as HE. They have
896-401: A cartridge case and it achieves obturation through a screw breech instead of a sliding block. Sometimes when reading about artillery the term separate loading ammunition will be used without clarification of whether a cartridge case is used or not, in which case it refers to the type of breech used. Heavy artillery pieces and naval artillery tend to use bagged charges and projectiles because
1024-494: A challenge because there was no way of ensuring that the impact mechanism contacted the target. Therefore, ball shells needed a time fuse that was ignited before or during firing and burned until the shell reached its target. Cast iron shells packed with gunpowder have been used in warfare since at least early 13th century China. Hollow, gunpowder-packed shells made of cast iron used during the Song dynasty (960-1279) are described in
1152-464: A concrete demolition 203 mm (8 in) shell 146 kg (322 lbs), a 280 mm (11 in) battleship shell about 300 kg (661 lbs), and a 460 mm (18 in) battleship shell over 1,500 kg (3,307 lbs). The Schwerer Gustav large-calibre gun fired shells that weighed between 4,800 kg (10,582 lbs) and 7,100 kg (15,653 lbs). During the 19th century, the British adopted
1280-521: A double wall of trenches and ramparts, and in the Congo forests concealed ditches and paths, along with the main works, often bristled with rows of sharpened stakes. Inner defenses were laid out to blunt an enemy penetration with a maze of defensive walls allowing for entrapment and crossfire on opposing forces. A military tactic of the Ashanti was to create powerful log stockades at key points. This
1408-412: A fixed round becomes too long or too heavy to load by a gun crew. Another issue is the inability to vary propellant charges to achieve different velocities and ranges. Lastly, there is the issue of resource usage since a fixed round uses a case, which can be an issue in a prolonged war if there are metal shortages. Separate loading cased charge ammunition has three main components: the fuzed projectile,
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#17327719498261536-412: A half-inch. The sabot was also intended to reduce jamming during loading. Despite the use of exploding shells, the use of smoothbore cannons firing spherical projectiles of shot remained the dominant artillery method until the 1850s. The mid–19th century saw a revolution in artillery, with the introduction of the first practical rifled breech loading weapons. The new methods resulted in the reshaping of
1664-643: A huge cloud of smoke and concealed shooters were given away by a cloud of smoke over the firing position. Guncotton , a nitrocellulose-based material, was discovered by Swiss chemist Christian Friedrich Schönbein in 1846. He promoted its use as a blasting explosive and sold manufacturing rights to the Austrian Empire . Guncotton was more powerful than gunpowder, but at the same time was somewhat more unstable. John Taylor obtained an English patent for guncotton; and John Hall & Sons began manufacture in Faversham . British interest waned after an explosion destroyed
1792-729: A map the fortresses appear to form the vertices of a quadrilateral . In the period between the end of the Napoleonic Wars and the Revolutions of 1848 , they were the only fully modernized and armed fortresses within the Empire. Starting from c. 1850, supplies and reinforcements were shipped to the positions through the new Venice - Milan railroad. The experience of the Second Italian Independence War of 1859, in which rifled guns had been used for
1920-697: A military context. A shell can hold a tracer . All explosive- and incendiary-filled projectiles, particularly for mortars , were originally called grenades , derived from the French word for pomegranate , so called because of the similarity of shape and that the multi-seeded fruit resembles the powder-filled, fragmentizing bomb. Words cognate with grenade are still used for an artillery or mortar projectile in some European languages. Shells are usually large-caliber projectiles fired by artillery, armoured fighting vehicles (e.g. tanks , assault guns , and mortar carriers ), warships , and autocannons . The shape
2048-413: A necessity for many cities. Amnya Fort in western Siberia has been described by archaeologists as one of the oldest known fortified settlements, as well as the northernmost Stone Age fort. In Bulgaria, near the town of Provadia a walled fortified settlement today called Solnitsata starting from 4700 BC had a diameter of about 300 feet (91 m), was home to 350 people living in two-storey houses, and
2176-409: A particular form of designating artillery. Field guns were designated by nominal standard projectile weight, while howitzers were designated by barrel caliber. British guns and their ammunition were designated in pounds , e.g., as "two-pounder" shortened to "2-pr" or "2-pdr". Usually, this referred to the actual weight of the standard projectile (shot, shrapnel, or high explosive), but, confusingly, this
2304-591: A result, very very few kotas still stand to this day. Notable kotas: During Muhammad 's era in Arabia, many tribes made use of fortifications. In the Battle of the Trench , the largely outnumbered defenders of Medina, mainly Muslims led by Islamic prophet Muhammad, dug a trench , which together with Medina's natural fortifications, rendered the confederate cavalry (consisting of horses and camels ) useless, locking
2432-431: A series of straight lines creating the central fortified area that gives this style of fortification its name. Explosive shell A shell , in a modern military context, is a projectile whose payload contains an explosive , incendiary , or other chemical filling. Originally it was called a bombshell , contrasting with solid shells used for early rifled artillery, but "shell" has come to be unambiguous in
2560-419: A small rocket motor built into its base to provide additional thrust. The second has a pyrotechnic device in its base that bleeds gas to fill the partial vacuum created behind the shell and hence reduce base-drag. These shell designs usually have reduced high-explosive filling to remain within the permitted mass for the projectile, and hence less lethality. The caliber of a shell is its diameter . Depending on
2688-482: A strong steel case, a bursting charge, and a fuse . The fuse detonates the bursting charge which shatters the case and scatters hot, sharp case pieces ( fragments , splinters ) at high velocity. Most of the damage to soft targets, such as unprotected personnel, is caused by shell pieces rather than by the blast. The term "shrapnel" is sometimes used to describe the shell pieces, but shrapnel shells functioned very differently and are long obsolete. The speed of fragments
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#17327719498262816-476: A thickness about 1/15th of the total diameter and filled with powder, saltpeter, pitch, coal and tallow. They were used to 'suffocate or expel the enemy in casemates, mines or between decks; for concealing operations; and as signals. During the First World War , shrapnel shells and explosive shells inflicted terrible casualties on infantry, accounting for nearly 70% of all war casualties and leading to
2944-455: Is semi-fixed ammunition. With semi-fixed ammunition the round comes as a complete package but the projectile and its case can be separated. The case holds a set number of bagged charges and the gun crew can add or subtract propellant to change range and velocity. The round is then reassembled, loaded, and fired. Advantages include easier handling for larger caliber rounds, while range and velocity can easily be varied by increasing or decreasing
3072-561: Is also an intermediate branch known as semi-permanent fortification. Castles are fortifications which are regarded as being distinct from the generic fort or fortress in that they are a residence of a monarch or noble and command a specific defensive territory. 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
3200-428: Is another example of a Gaulish fortified settlement. The term casemate wall is used in the archaeology of Israel and the wider Near East , having the meaning of a double wall protecting a city or fortress, with transverse walls separating the space between the walls into chambers. These could be used as such, for storage or residential purposes, or could be filled with soil and rocks during siege in order to raise
3328-548: 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 labour being available. An example of this is the construction of Roman forts in England and in other Roman territories where camps were set up with the intention of staying for some time, but not permanently. Castles are fortifications which are regarded as being distinct from
3456-519: Is formally known as poliorcetics . In some texts, this latter term also applies to the art of building a fortification. Fortification is usually divided into two branches: 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—for example breastworks —and often known as fieldworks or earthworks, are extemporized by troops in
3584-404: Is generally most suitable but cupronickel or gilding metal were also used. Although an early percussion fuze appeared in 1650 that used a flint to create sparks to ignite the powder, the shell had to fall in a particular way for this to work and this did not work with spherical projectiles. An additional problem was finding a suitably stable "percussion powder". Progress was not possible until
3712-443: Is obsolete. Typically, the thickness of the metal body was about a sixth of their diameter, and they were about two-thirds the weight of solid shot of the same caliber. To ensure that shells were loaded with their fuses toward the muzzle, they were attached to wooden bottoms called sabots . In 1819, a committee of British artillery officers recognized that they were essential stores and in 1830 Britain standardized sabot thickness as
3840-555: Is usually a cylinder topped by an ogive -tipped nose cone for good aerodynamic performance , and possibly with a tapered boat tail ; but some specialized types differ widely. Gunpowder is a low explosive , meaning it will not create a concussive, brisant explosion unless it is contained, as in a modern-day pipe bomb or pressure cooker bomb . Early grenades were hollow cast-iron balls filled with gunpowder, and "shells" were similar devices designed to be shot from artillery in place of solid cannonballs ("shot"). Metonymically ,
3968-746: The British Raj are found in the mainland Indian subcontinent (modern day India , Pakistan , Bangladesh and Nepal ). "Fort" is the word used in India for all old fortifications. Numerous Indus Valley Civilization sites exhibit evidence of fortifications. By about 3500 BC, 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 neighbouring communities bickered constantly about
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4096-637: The Indus Valley Civilization were the first small cities to be fortified. In ancient Greece , large stone walls had been built in Mycenaean Greece , such as the ancient site of Mycenae (known for the huge stone blocks of its ' cyclopean ' walls). A Greek phrourion was a fortified collection of buildings used as a military garrison , and is the equivalent of the Roman castellum or fortress. These constructions mainly served
4224-769: The Industrial Revolution that Armstrong was able to construct a viable solution. Another innovative feature was what Armstrong called its "grip", which was essentially a squeeze bore ; the 6 inches of the bore at the muzzle end was of slightly smaller diameter, which centered the shell before it left the barrel and at the same time slightly swaged down its lead coating, reducing its diameter and slightly improving its ballistic qualities. Rifled guns were also developed elsewhere – by Major Giovanni Cavalli and Baron Martin von Wahrendorff in Sweden, Krupp in Germany and
4352-1205: The Maratha Empire . A large majority of forts in India are in North India. The most notable forts are the Red Fort at Old Delhi , the Red Fort at Agra , the Chittor Fort and Mehrangarh Fort in Rajasthan , the Ranthambhor Fort , Amer Fort and Jaisalmer Fort also in Rajasthan and Gwalior Fort in Madhya Pradesh . Arthashastra , the Indian treatise on military strategy describes six major types of forts differentiated by their major modes of defenses. Forts in Sri Lanka date back thousands of years, with many being built by Sri Lankan kings. These include several walled cities. With
4480-586: The Mediterranean . The fortifications were continuously being expanded and improved. Around 600 BC, in Heuneburg , Germany, forts were constructed with a limestone foundation supported by a mudbrick wall approximately 4 metres tall, probably topped by a roofed walkway, thus reaching a total height of 6 metres. The wall was clad with lime plaster, regularly renewed. Towers protruded outwards from it. The Oppidum of Manching (German: Oppidum von Manching)
4608-569: The Napoleonic wars . Most of the colonial forts were garrisoned up until the early 20th century. The coastal forts had coastal artillery manned by the Ceylon Garrison Artillery during the two world wars. Most of these were abandoned by the military but retained civil administrative officers, while others retained military garrisons, which were more administrative than operational. Some were reoccupied by military units with
4736-527: The Nordic states and in Britain , the fortifications of Berwick-upon-Tweed and the harbour archipelago of Suomenlinna at Helsinki being fine examples. During the 18th century, it was found that the continuous enceinte , or main defensive enclosure of a bastion fortress, could not be made large enough to accommodate the enormous field armies which were increasingly being employed in Europe; neither could
4864-707: The Old City of Shanghai , Suzhou , Xi'an and the walled villages of Hong Kong . The famous walls of the Forbidden City in Beijing were established in the early 15th century by the Yongle Emperor . The Forbidden City made up the inner portion of the Beijing city fortifications . During the Spanish Era several forts and outposts were built throughout the archipelago. Most notable is Intramuros ,
4992-594: The Republic of Venice at Jadra in 1376. Shells with fuses were used at the 1421 siege of St Boniface in Corsica . These were two hollowed hemispheres of stone or bronze held together by an iron hoop. At least since the 16th century grenades made of ceramics or glass were in use in Central Europe. A hoard of several hundred ceramic grenades dated to the 17th century was discovered during building works in front of
5120-462: The Royal Arsenal at Woolwich . The piece was rifled , which allowed for a much more accurate and powerful action. Although rifling had been tried on small arms since the 15th century, the necessary machinery to accurately rifle artillery only became available in the mid-19th century. Martin von Wahrendorff and Joseph Whitworth independently produced rifled cannons in the 1840s, but it
5248-618: The Siege of Ta'if in January 630, Muhammad ordered his followers to attack enemies who fled from the Battle of Hunayn and sought refuge in the fortress of Taif. The entire city of Kerma in Nubia (present day Sudan) was encompassed by fortified walls surrounded by a ditch. Archaeology has revealed various Bronze Age bastions and foundations constructed of stone together with either baked or unfired brick. The walls of Benin are described as
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5376-634: The Tang dynasty (618–907 AD). The Great Wall of China had been built since the Qin dynasty (221–207 BC), although its present form was mostly an engineering feat and remodelling of the Ming dynasty (1368–1644 AD). In addition to the Great Wall, a number of Chinese cities also employed the use of defensive walls to defend their cities. Notable Chinese city walls include the city walls of Hangzhou , Nanjing ,
5504-828: 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 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. A number of forts dating from the Later Stone Age to
5632-585: The Wiard gun in the United States. However, rifled barrels required some means of engaging the shell with the rifling. Lead coated shells were used with the Armstrong gun , but were not satisfactory so studded projectiles were adopted. However, these did not seal the gap between shell and barrel. Wads at the shell base were also tried without success. In 1878, the British adopted a copper " gas-check " at
5760-604: The fuzed projectile, the casing to hold the propellants and primer , and the single propellant charge. Everything is included in a ready-to-use package and in British ordnance terms is called fixed quick firing . Often guns which use fixed ammunition use sliding-block or sliding-wedge breeches and the case provides obturation which seals the breech of the gun and prevents propellant gasses from escaping. Sliding block breeches can be horizontal or vertical. Advantages of fixed ammunition are simplicity, safety, moisture resistance and speed of loading. Disadvantages are eventually
5888-401: The "Great Wall of Brodgar" it was 4 metres (13 ft) thick and 4 metres tall. The wall had some symbolic or ritualistic function. The Assyrians deployed large labour forces to build new palaces , temples and defensive walls. In Bronze Age Malta , some settlements also began to be fortified. The most notable surviving example is Borġ in-Nadur , where a bastion built in around 1500 BC
6016-490: The 17th century onwards. The British adopted parachute lightballs in 1866 for 10-, 8- and 5 1 ⁄ 2 -inch calibers. The 10-inch was not officially declared obsolete until 1920. Smoke balls also date back to the 17th century, British ones contained a mix of saltpetre, coal, pitch, tar, resin, sawdust, crude antimony and sulphur. They produced a "noisome smoke in abundance that is impossible to bear". In 19th-century British service, they were made of concentric paper with
6144-530: The 19th and early 20th centuries. The advances in modern warfare since World War I have made large-scale fortifications obsolete in most situations. Many United States Army installations are known as forts, although they are not always fortified. During the pioneering era of North America, many outposts on the frontiers, even non-military outposts, were referred to generically as forts. Larger military installations may be called fortresses; smaller ones were once known as fortalices. The word fortification can refer to
6272-436: The 19th century. Until the mid 19th century, shells remained as simple exploding spheres that used gunpowder, set off by a slow burning fuse. They were usually made of cast iron , but bronze , lead , brass and even glass shell casings were experimented with. The word bomb encompassed them at the time, as heard in the lyrics of The Star-Spangled Banner ("the bombs bursting in air"), although today that sense of bomb
6400-549: The Austrian factories blew up in 1862, Thomas Prentice & Company began manufacturing guncotton in Stowmarket in 1863; and British War Office chemist Sir Frederick Abel began thorough research at Waltham Abbey Royal Gunpowder Mills leading to a manufacturing process that eliminated the impurities in nitrocellulose making it safer to produce and a stable product safer to handle. Abel patented this process in 1865, when
6528-419: The Faversham factory in 1847. Austrian Baron Wilhelm Lenk von Wolfsberg built two guncotton plants producing artillery propellant, but it was dangerous under field conditions, and guns that could fire thousands of rounds using gunpowder would reach their service life after only a few hundred shots with the more powerful guncotton. Small arms could not withstand the pressures generated by guncotton. After one of
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#17327719498266656-577: The First World War (such as the BL 60-pounder gun , RML 2.5 inch Mountain Gun , 4 inch gun, 4.5 inch howitzer) through to the end of World War II (5.5 inch medium gun, 25-pounder gun-howitzer , 17-pounder tank gun), but the majority of naval guns were by caliber. After the end of World War II, field guns were designated by caliber. There are many different types of shells. The principal ones include: With
6784-758: The German super- railway guns , Gustav and Dora , which were 800 mm (31.5 in) in caliber. Very large shells have been replaced by rockets , missiles , and bombs . Today the largest shells in common use are 155 mm (6.1 in). Gun calibers have standardized around a few common sizes, especially in the larger range, mainly due to the uniformity required for efficient military logistics. Shells of 105 and 155 mm for artillery with 105 and 120 mm for tank guns are common in NATO allied countries. Shells of 122, 130, and 152 mm for artillery with 100, 115, and 125 mm for tank guns, remain in common usage among
6912-593: The Indus Valley Civilization were fortified. Forts also appeared in urban cities of the Gangetic valley during the second urbanisation period between 600 and 200 BC, and as many as 15 fortification sites have been identified by archaeologists throughout the Gangetic valley, such as Kaushambi , Mahasthangarh , Pataliputra , Mathura , Ahichchhatra , Rajgir , and Lauria Nandangarh . The earliest Mauryan period brick fortification occurs in one of
7040-641: The Iron Age and peaking in Iron Age II (10th–6th century BC). However, the construction of casemate walls had begun to be replaced by sturdier solid walls by the 9th century BC , probably due the development of more effective battering rams by the Neo-Assyrian Empire . Casemate walls could surround an entire settlement, but most only protected part of it. The three different types included freestanding casemate walls, then integrated ones where
7168-551: The Royal Artillery was adopted by the army. It was a wooden fuze about 6 inches long and used shear wire to hold blocks between the fuze magazine and a burning match. The match was ignited by propellant flash and the shear wire broke on impact. A British naval percussion fuze made of metal did not appear until 1861. Gunpowder was used as the only form of explosive up until the end of the 19th century. Guns using black powder ammunition would have their view obscured by
7296-458: The adoption of steel combat helmets on both sides. Frequent problems with shells led to many military disasters with dud shells, most notably during the 1916 Battle of the Somme . Shells filled with poison gas were used from 1917 onwards. Artillery shells are differentiated by how the shell is loaded and propelled, and the type of breech mechanism. Fixed ammunition has three main components:
7424-518: The ancient site of Mycenae (famous for the huge stone blocks of its ' cyclopean ' walls). In classical era Greece , the city of Athens built two parallel stone walls, called the Long Walls , that reached their fortified seaport at Piraeus a few miles away. In Central Europe , the Celts built large fortified settlements known as oppida , whose walls seem partially influenced by those built in
7552-410: The arrival of cannons on the 14th century battlefield . Fortifications in the age of black powder 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
7680-499: The base of their studded projectiles and in 1879 tried a rotating gas check to replace the studs, leading to the 1881 automatic gas-check. This was soon followed by the Vavaseur copper driving band as part of the projectile. The driving band rotated the projectile, centered it in the bore and prevented gas escaping forwards. A driving band has to be soft but tough enough to prevent stripping by rotational and engraving stresses. Copper
7808-542: The bursting charges in APHE became ever smaller to non-existent, especially in smaller caliber shells, e.g. Panzergranate 39 with only 0.2% HE filling. Although smokeless powders were used as a propellant, they could not be used as the substance for the explosive warhead, because shock sensitivity sometimes caused detonation in the artillery barrel at the time of firing. Picric acid was the first high-explosive nitrated organic compound widely considered suitable to withstand
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#17327719498267936-559: The casing to hold the propellants and primer, and the bagged propellant charges. The components are usually separated into two or more parts. In British ordnance terms, this type of ammunition is called separate quick firing . Often guns which use separate loading cased charge ammunition use sliding-block or sliding-wedge breeches and during World War I and World War II Germany predominantly used fixed or separate loading cased charges and sliding block breeches even for their largest guns. A variant of separate loading cased charge ammunition
8064-532: The combustion temperature and hence erosion and barrel wear. Cordite could be made to burn more slowly which reduced maximum pressure in the chamber (hence lighter breeches, etc.), but longer high pressure – significant improvements over gunpowder. Cordite could be made in any desired shape or size. The creation of cordite led to a lengthy court battle between Nobel, Maxim, and another inventor over alleged British patent infringement. A variety of fillings have been used in shells throughout history. An incendiary shell
8192-566: The control of prime agricultural land. The fortification varies by site. While Dholavira has stone-built fortification walls, Harrapa is fortified using baked bricks; sites such as Kalibangan exhibit mudbrick fortifications with bastions and Lothal has a quadrangular fortified layout. Evidence also suggested of fortifications in Mohenjo-daro . Even a small town—for instance, Kotada Bhadli, exhibiting sophisticated fortification-like bastions—shows that nearly all major and minor towns of
8320-407: The creation of some towns built around castles. Medieval-style fortifications were largely made obsolete by the arrival of cannons in the 14th century. Fortifications in the age of black powder 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
8448-964: The current level of military development. During the Renaissance era , the Venetian Republic raised great walls around cities, and the finest examples, among others, are in Nicosia (Cyprus), Rocca di Manerba del Garda (Lombardy), and Palmanova (Italy), or Dubrovnik (Croatia), which proved to be futile against attacks but still stand to this day. Unlike the Venetians, the Ottomans used to build smaller fortifications but in greater numbers, and only rarely fortified entire settlements such as Počitelj , Vratnik , and Jajce in Bosnia . Medieval-style fortifications were largely made obsolete by
8576-434: The curve was a segment of a circle having a radius of twice the shell caliber. After that war, ogive shapes became more complex and elongated. From the 1960s, higher quality steels were introduced by some countries for their HE shells, this enabled thinner shell walls with less weight of metal and hence a greater weight of explosive. Ogives were further elongated to improve their ballistic performance. Advances in metallurgy in
8704-435: The defences be constructed far enough away from the fortress town to protect the inhabitants from bombardment by the besiegers, the range of whose guns was steadily increasing as better manufactured weapons were introduced. Threfore, since refortifying the Prussian fortress cities of Koblenz and Cologne after 1815, the principle of the ring fortress or girdle fortress was used: forts, each several hundred metres out from
8832-413: The discovery of mercury fulminate in 1800, leading to priming mixtures for small arms patented by the Rev Alexander Forsyth , and the copper percussion cap in 1818. The percussion fuze was adopted by Britain in 1842. Many designs were jointly examined by the army and navy, but were unsatisfactory, probably because of the safety and arming features. However, in 1846 the design by Quartermaster Freeburn of
8960-429: The early Ming Dynasty Chinese military manual Huolongjing , written in the mid 14th century. The History of Jin 《金史》 (compiled by 1345) states that in 1232, as the Mongol general Subutai (1176–1248) descended on the Jin stronghold of Kaifeng , the defenders had a " thunder crash bomb " which "consisted of gunpowder put into an iron container ... then when the fuse was lit (and the projectile shot off) there
9088-491: The escalation of the Sri Lankan Civil War ; Jaffna fort , for example, came under siege several times. Large tempered earth (i.e. rammed earth ) walls were built in ancient China since the Shang dynasty ( c. 1600 –1050 BC); 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
9216-400: The field, perhaps assisted by such local labour and tools as may be procurable and with materials that do not require much preparation, such as soil, brushwood, and light timber , or sandbags (see sangar ). An example of field fortification was the construction of Fort Necessity by George Washington in 1754. There is also an intermediate branch known as semi-permanent fortification. This
9344-538: The first being Germany and Austria which introduced new weapons in 1888. Subsequently, Poudre B was modified several times with various compounds being added and removed. Krupp began adding diphenylamine as a stabilizer in 1888. Britain conducted trials on all the various types of propellant brought to their attention, but were dissatisfied with them all and sought something superior to all existing types. In 1889, Sir Frederick Abel , James Dewar and W. Kellner patented (No. 5614 and No. 11,664 in
9472-632: The first time by the Italian Army , pushed the Austrians to build a second line of eight forts, about 4 kilometers from the main line (completed in the spring of 1866), pivoting around Verona . 45°17′39″N 10°58′06″E / 45.29417°N 10.96833°E / 45.29417; 10.96833 Fortresses From very early history to modern times, defensive walls have often been necessary for cities to survive in an ever-changing world of invasion and conquest . Some settlements in
9600-475: The fortification to allow defensive cannonry interlocking fields of fire to cover all approaches to the lower and thus more vulnerable walls. The evolution of this new style of fortification can be seen in transitional forts such as Sarzanello in North West Italy which was built between 1492 and 1502. Sarzanello consists of both crenellated walls with towers typical of the medieval period but also has
9728-532: The frontiers of the Nile Valley to protect against invaders from neighbouring territories, as well as circle-shaped mud brick walls around their cities. Many of the fortifications of the ancient world were built with mud brick, often leaving them no more than mounds of dirt for today's archaeologists. A massive prehistoric stone wall surrounded the ancient temple of Ness of Brodgar 3200 BC in Scotland . Named
9856-504: The generic fort or fortress in that it describes a residence of a monarch or noble and commands a specific defensive territory. An example of this is the massive medieval castle of Carcassonne . Defensive fences for protecting humans and domestic animals against predators was used long before the appearance of writing and began "perhaps with primitive man blocking the entrances of his caves for security from large carnivores ". From very early history to modern times, walls have been
9984-428: The gun to achieve greater range and accuracy than existing smooth-bore muzzle-loaders with a smaller powder charge. The gun was also a breech-loader. Although attempts at breech-loading mechanisms had been made since medieval times, the essential engineering problem was that the mechanism could not withstand the explosive charge. It was only with the advances in metallurgy and precision engineering capabilities during
10112-532: The height of the Maguindanao Sultanate 's power, they blanketed the areas around Western Mindanao with kotas and other fortifications to block the Spanish advance into the region. These kotas were usually made of stone and bamboo or other light materials and surrounded by trench networks. As a result, some of these kotas were burned easily or destroyed. With further Spanish campaigns in the region,
10240-436: The historical period and national preferences, this may be specified in millimeters , centimeters , or inches . The length of gun barrels for large cartridges and shells (naval) is frequently quoted in terms of the ratio of the barrel length to the bore size, also called caliber . For example, the 16"/50 caliber Mark 7 gun is 50 calibers long, that is, 16"×50=800"=66.7 feet long. Some guns, mainly British, were specified by
10368-563: The industrial era allowed for the construction of rifled breech-loading guns that could fire at a much greater muzzle velocity . After the British artillery was shown up in the Crimean War as having barely changed since the Napoleonic Wars , the industrialist William Armstrong was awarded a contract by the government to design a new piece of artillery. Production started in 1855 at the Elswick Ordnance Company and
10496-413: The inner wall was part of the outer buildings of the settlement, and finally filled casemate walls, where the rooms between the walls were filled with soil right away, allowing for a quick, but nevertheless stable construction of particularly high walls. 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
10624-402: The intervals between them. The arrival of explosive shells in the 19th century led to yet another stage in the evolution of fortification. Star forts did not fare well against the effects of high explosives 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,
10752-410: The introduction of the first ironclads in the 1850s and 1860s, it became clear that shells had to be designed to effectively pierce the ship armour. A series of British tests in 1863 demonstrated that the way forward lay with high-velocity lighter shells. The first pointed armour-piercing shell was introduced by Major Palliser in 1863. Approved in 1867, Palliser shot and shell was an improvement over
10880-413: 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
11008-480: 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, hundreds of settlements of all sizes were founded all across Europe, which very often obtained
11136-485: The name Lyddite . Japan followed with an "improved" formula known as shimose powder . In 1889, a similar material, a mixture of ammonium cresylate with trinitrocresol, or an ammonium salt of trinitrocresol, started to be manufactured under the name ecrasite in Austria-Hungary . By 1894, Russia was manufacturing artillery shells filled with picric acid. Ammonium picrate (known as Dunnite or explosive D )
11264-486: The names of Abel and Dewar) a new formulation that was manufactured at the Royal Gunpowder Factory at Waltham Abbey. It entered British service in 1891 as Cordite Mark 1. Its main composition was 58% nitro-glycerine, 37% guncotton and 3% mineral jelly. A modified version, Cordite MD, entered service in 1901, this increased guncotton to 65% and reduced nitro-glycerine to 30%, this change reduced
11392-421: The need for a pressure-holding casing, so the casing of later shells only needs to contain the munition, and, if desired, to produce shrapnel. The term "shell," however, was sufficiently established that it remained as the term for such munitions. Hollow shells filled with gunpowder needed a fuse that was either impact triggered ( percussion ) or time delayed. Percussion fuses with a spherical projectile presented
11520-470: The number of propellant charges. Disadvantages include more complexity, slower loading, less safety, less moisture resistance, and the metal cases can still be a material resource issue. In separate loading bagged charge ammunition there are three main components: the fuzed projectile, the bagged charges and the primer. Like separate loading cased charge ammunition, the number of propellant charges can be varied. However, this style of ammunition does not use
11648-539: The old walled city of Manila located along the southern bank of the Pasig River . The historic city was home to centuries-old churches, schools, convents, government buildings and residences, the best collection of Spanish colonial architecture before much of it was destroyed by the bombs of World War II . Of all the buildings within the 67-acre city, only one building, the San Agustin Church, survived
11776-460: The ordinary elongated shot of the time. Palliser shot was made of cast iron , the head being chilled in casting to harden it, using composite molds with a metal, water cooled portion for the head. Britain also deployed Palliser shells in the 1870s–1880s. In the shell, the cavity was slightly larger than in the shot and was filled with 1.5% gunpowder instead of being empty, to provide a small explosive effect after penetrating armour plating. The shell
11904-440: The original enceinte, were carefully sited so as to make best use of the terrain and to be capable of mutual support with the neighbouring forts. Gone were citadels surrounding towns: forts were to be moved to the outside of the cities some 12 km to keep the enemy at a distance so their artillery could not bombard the city center. From now on a ring of forts were to be built at a spacing that would allow them to effectively cover
12032-738: The outset of colonial rule in the Indian Ocean , Sri Lanka was occupied by several major colonial empires that from time to time became the dominant power in the Indian Ocean. The colonists built several western-style forts, mostly in and around the coast of the island. The first to build colonial forts in Sri Lanka were the Portuguese ; these forts were captured and later expanded by the Dutch . The British occupied these Dutch forts during
12160-402: The powder fuse was subject to considerable trial and error. Early powder-burning fuses had to be loaded fuse down to be ignited by firing or a portfire or slow match put down the barrel to light the fuse. Other shells were wrapped in bitumen cloth, which would ignite during the firing and in turn ignite a powder fuse. Nevertheless, shells came into regular use in the 16th century, for example,
12288-409: The practice of improving an area's defense with defensive works. City walls are fortifications but are not necessarily called fortresses. The art of setting out a military camp or constructing a fortification traditionally has been called castrametation since the time of the Roman legions . Laying siege to a fortification and of destroying it is commonly called siegecraft or siege warfare and
12416-471: The purpose of a watch tower, to guard certain roads, passes, and borders. Though smaller than a real fortress, they acted as a border guard rather than a real strongpoint to watch and maintain the border. The art of setting out a military camp or constructing a fortification traditionally has been called "castrametation" since the time of the Roman legions . Fortification is usually divided into two branches: permanent fortification and field fortification. There
12544-432: The regions of Eastern Europe, Western Asia, Northern Africa, and Eastern Asia. Most common calibers have been in use for many decades, since it is logistically complex to change the caliber of all guns and ammunition stores. The weight of shells increases by and large with caliber. A typical 155 mm (6.1 in) shell weighs about 50 kg (110 lbs), a common 203 mm (8 in) shell about 100 kg (220 lbs),
12672-656: The resistance of the outer wall against battering rams. Originally thought to have been introduced to the region by the Hittites , this has been disproved by the discovery of examples predating their arrival, the earliest being at Ti'inik (Taanach) where such a wall has been dated to the 16th century BC . Casemate walls became a common type of fortification in the Southern Levant between the Middle Bronze Age (MB) and Iron Age II, being more numerous during
12800-429: The right of fortification soon afterward. The founding of urban centres 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
12928-507: The second Austrian guncotton factory exploded. After the Stowmarket factory exploded in 1871, Waltham Abbey began production of guncotton for torpedo and mine warheads. In 1884, Paul Vieille invented a smokeless powder called Poudre B (short for poudre blanche —white powder, as distinguished from black powder ) made from 68.2% insoluble nitrocellulose , 29.8% soluble nitrocellusose gelatinized with ether and 2% paraffin. This
13056-515: The shock of firing in conventional artillery . In 1885, based on research of Hermann Sprengel, French chemist Eugène Turpin patented the use of pressed and cast picric acid in blasting charges and artillery shells . In 1887, the French government adopted a mixture of picric acid and guncotton under the name Melinite . In 1888, Britain started manufacturing a very similar mixture in Lydd , Kent, under
13184-476: The spherical shell into its modern recognizable cylindro-conoidal form. This shape greatly improved the in-flight stability of the projectile and meant that the primitive time fuzes could be replaced with the percussion fuze situated in the nose of the shell. The new shape also meant that further, armour-piercing designs could be used. During the 20th century, shells became increasingly streamlined. In World War I, ogives were typically two circular radius head (crh) –
13312-489: The stockades by mounting old-fashioned bayonet charges, after laying down some covering fire. Defensive works were of importance in the tropical African Kingdoms. In the Kingdom of Kongo field fortifications were characterized by trenches and low earthen embankments. Such strongpoints ironically, sometimes held up much better against European cannon than taller, more imposing structures. Roman forts and hill forts were
13440-438: The stupa mounds of Lauria Nandangarh, which is 1.6 km in perimeter and oval in plan and encloses a habitation area. Mundigak ( c. 2500 BC ) in present-day south-east Afghanistan has defensive walls and square bastions of sun dried bricks. India currently has over 180 forts, with the state of Maharashtra alone having over 70 forts, which are also known as durg , many of them built by Shivaji , founder of
13568-636: The sultanate was subdued and a majority of kotas dismantled or destroyed. kotas were not only used by the Muslims as defense against Spaniards and other foreigners, renegades and rebels also built fortifications in defiance of other chiefs in the area. During the American occupation, rebels built strongholds and the datus, rajahs, or sultans often built and reinforced their kotas in a desperate bid to maintain rule over their subjects and their land. Many of these forts were also destroyed by American expeditions, as
13696-418: The term "shell", from the casing, came to mean the entire munition . In a gunpowder-based shell, the casing was intrinsic to generating the explosion, and thus had to be strong and thick. Its fragments could do considerable damage, but each shell broke into only a few large pieces. Further developments led to shells which would fragment into smaller pieces. The advent of high explosives such as TNT removed
13824-485: The two sides in a stalemate. Hoping to make several attacks at once, the confederates persuaded the Medina-allied Banu Qurayza to attack the city from the south. However, Muhammad's diplomacy derailed the negotiations, and broke up the confederacy against him. The well-organized defenders, the sinking of confederate morale, and poor weather conditions caused the siege to end in a fiasco. During
13952-499: The walls were sunk into ditches fronted by earth slopes to improve protection. The arrival of explosive shells in the 19th century led to another stage in the evolution of fortification. Star forts did not fare well against the effects of high explosives, 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. Steel -and- concrete fortifications were common during
14080-559: The war. Partial listing of Spanish forts: The Ivatan people of the northern islands of Batanes built their so-called idjang on hills and elevated areas to protect themselves during times of war. These fortifications were likened to European castles because of their purpose. Usually, the only entrance to the castles would be via a rope ladder that would only be lowered for the villagers and could be kept away when invaders arrived. The Igorots built forts made of stone walls that averaged several meters in width and about two to three times
14208-528: The weight and size of the projectiles and propelling charges can be more than a gun crew can manage. Advantages include easier handling for large rounds, decreased metal usage, while range and velocity can be varied by using more or fewer propellant charges. Disadvantages include more complexity, slower loading, less safety and less moisture resistance. Extended-range shells are sometimes used. These special shell designs may be rocket-assisted projectiles (RAP) or base bleed (BB) to increase range. The first has
14336-462: The weight of their shells (see below). Explosive rounds as small as 12.7 x 82 mm and 13 x 64 mm have been used on aircraft and armoured vehicles, but their small explosive yields have led some nations to limit their explosive rounds to 20mm (.78 in) or larger. International Law precludes the use of explosive ammunition for use against individual persons, but not against vehicles and aircraft. The largest shells ever fired during war were those from
14464-410: The width in height around 2000 BC. The Muslim Filipinos of the south built strong fortresses called kota or moong to protect their communities. Usually, many of the occupants of these kotas are entire families rather than just warriors. Lords often had their own kotas to assert their right to rule, it served not only as a military installation but as a palace for the local Lord. It is said that at
14592-634: The world's second longest man-made structure, as well as the most extensive earthwork in the world, by the Guinness Book of Records, 1974 . The walls may have been constructed between the thirteenth and mid-fifteenth century CE or, during the first millennium CE. Strong citadels were also built other in areas of Africa. Yorubaland for example had several sites surrounded by the full range of earthworks and ramparts seen elsewhere, and sited on ground. This improved defensive potential—such as hills and ridges. Yoruba fortifications were often protected with
14720-534: Was Armstrong's gun that was first to see widespread use during the Crimean War. The cast iron shell of the Armstrong gun was similar in shape to a Minié ball and had a thin lead coating which made it fractionally larger than the gun's bore and which engaged with the gun's rifling grooves to impart spin to the shell. This spin, together with the elimination of windage as a result of the tight fit, enabled
14848-407: Was a great explosion the noise whereof was like thunder, audible for more than thirty miles, and the vegetation was scorched and blasted by the heat over an area of more than half a mou . When hit, even iron armour was quite pierced through." Archeological examples of these shells from the 13th century Mongol invasions of Japan have been recovered from a shipwreck. Shells were used in combat by
14976-430: Was a large Celtic proto-urban or city-like settlement at modern-day Manching (near Ingolstadt), Bavaria (Germany). The settlement was founded in the 3rd century BC and existed until c. 50–30 BC . It reached its largest extent during the late La Tène period (late 2nd century BC), when it had a size of 380 hectares. At that time, 5,000 to 10,000 people lived within its 7.2 km long walls. The oppidum of Bibracte
15104-464: Was adopted for the Lebel rifle. Vieille's powder revolutionized the effectiveness of small guns, because it gave off almost no smoke and was three times more powerful than black powder. Higher muzzle velocity meant a flatter trajectory and less wind drift and bullet drop, making 1000 meter shots practicable. Other European countries swiftly followed and started using their own versions of Poudre B,
15232-540: Was correspondingly slightly longer than the shot to compensate for the lighter cavity. The powder filling was ignited by the shock of impact and hence did not require a fuze. However, ship armour rapidly improved during the 1880s and 1890s, and it was realised that explosive shells with steel had advantages including better fragmentation and resistance to the stresses of firing. These were cast and forged steel. AP shells containing an explosive filling were initially distinguished from their non-HE counterparts by being called
15360-603: Was employed in later wars against the British to block British advances. Some of these fortifications were over a hundred yards long, with heavy parallel tree trunks. They were impervious to destruction by artillery fire. Behind these stockades, numerous Ashanti soldiers were mobilized to check enemy movement. While formidable in construction, many of these strongpoints failed because Ashanti guns, gunpowder and bullets were poor, and provided little sustained killing power in defense. Time and time again British troops overcame or bypassed
15488-521: Was encircled by a fortified wall. The huge walls around the settlement, which were built very tall and with stone blocks which are 6 feet (1.8 m) high and 4.5 feet (1.4 m) thick, make it one of the earliest walled settlements in Europe but it is younger than the walled town of Sesklo in Greece from 6800 BC. Uruk in ancient Sumer ( Mesopotamia ) is one of the world's oldest known walled cities . The Ancient Egyptians also built fortresses on
15616-630: Was filled with molten iron and was intended to break up on impact with an enemy ship, splashing molten iron on the target. It was used by the Royal Navy between 1860 and 1869, replacing heated shot as an anti-ship, incendiary projectile. Two patterns of incendiary shell were used by the British in World War ;I, one designed for use against Zeppelins. Similar to incendiary shells were star shells, designed for illumination rather than arson. Sometimes called lightballs they were in use from
15744-435: Was found. Exceptions were few—notably, ancient Sparta and ancient Rome did not have walls for a long time, choosing to rely on their militaries for defence 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 ancient Greece , large stone walls had been built in Mycenaean Greece , such as
15872-430: Was invented by Valturio in 1460. The carcass shell was first used by the French under Louis XIV in 1672. Initially in the shape of an oblong in an iron frame (with poor ballistic properties) it evolved into a spherical shell. Their use continued well into the 19th century. A modern version of the incendiary shell was developed in 1857 by the British and was known as Martin's shell after its inventor. The shell
16000-459: Was not always the case. Some were named after the weights of obsolete projectile types of the same caliber, or even obsolete types that were considered to have been functionally equivalent. Also, projectiles fired from the same gun, but of non-standard weight, took their name from the gun. Thus, conversion from "pounds" to an actual barrel diameter requires consulting a historical reference. A mixture of designations were in use for land artillery from
16128-478: Was published by Giovanni Battista Zanchi in 1554. Fortifications also extended in depth, with protected batteries for defensive cannonry, to allow them to engage attacking cannons to keep them at a distance and prevent them from bearing directly on the vulnerable walls. The result was star shaped fortifications with tier upon tier of hornworks and bastions , of which Fort Bourtange is an excellent example. There are also extensive fortifications from this era in
16256-506: Was still in wide use in World War II . The percentage of shell weight taken up by its explosive fill increased steadily throughout the 20th Century. Less than 10% was usual in the first few decades; by World War II , leading designs were around 15%. However, British researchers in that war identified 25% as being the optimal design for anti-personnel purposes, based on the recognition that far smaller fragments than hitherto would give
16384-650: Was used by the United States beginning in 1906. Germany began filling artillery shells with TNT in 1902. Toluene was less readily available than phenol, and TNT is less powerful than picric acid, but the improved safety of munitions manufacturing and storage caused the replacement of picric acid by TNT for most military purposes between the World Wars. However, pure TNT was expensive to produce and most nations made some use of mixtures using cruder TNT and ammonium nitrate, some with other compounds included. These fills included Ammonal, Schneiderite and Amatol . The latter
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