Heritage Documentation Programs
Heritage Documentation Programs is a division of the U. S. National Park Service responsible for administering the Historic American Buildings Survey, Historic American Engineering Record, Historic American Landscapes Survey; these programs were established to document historic places in the United States. Records consist of measured drawings, archival photographs, written reports, are archived in the Prints and Photographs Division of the Library of Congress. In 1933, NPS established the Historic American Buildings Survey following a proposal by Charles E. Peterson, a young landscape architect in the agency, it was founded as a constructive make-work program for architects and photographers left jobless by the Great Depression. Guided by field instructions from Washington, D. C. the first HABS recorders were tasked with documenting a representative sampling of America's architectural heritage. By creating an archive of historic architecture, HABS provided a database of primary source material and documentation for the then-fledgling historic preservation movement.
Earlier private projects included the White Pine Series of Architectural Monographs, many contributors to which joined the HABS program. Notable HABS photographers include Jack Boucher; the Historic American Engineering Record program was founded on January 10, 1969, by NPS and the American Society of Civil Engineers. HAER documents historic mechanical and engineering artifacts. Since the advent of HAER, the combined program is called "HABS/HAER". Today much of the work of HABS/HAER is done by student teams during the summer, or as part of college-credit classwork. Eric DeLony headed HAER from 1971 to 2003. In October 2000, NPS and the American Society of Landscape Architects established a sister program, the Historic American Landscapes Survey, to systematically document historic American landscapes. A predecessor, the Historic American Landscape and Garden Project, recorded historic Massachusetts gardens between 1935 and 1940; that project was funded by the Works Progress Administration, but was administered by HABS, which supervised the collection of records.
The permanent collection of HABS/HAER/HALS are housed at the Library of Congress, established in 1790 as the replacement reference library of the United States Congress. It has since been expanded to serve as the National Library of the United States. S. publishers are required to deposit a copy of every copyrighted and published work, book monograph and magazine. As a branch of the United States Government, its created works are in the public domain in the US. Many images and documents are available through the Prints and Photographs Online Catalog, including proposed and existing structures. Jack Boucher, former HABS/HAER photographer Jet Lowe, former HAER photographer National Register of Historic Places Notes Further reading "HAER: 30 Years of Recording Our Technological Heritage". IA, The Journal of the Society for Industrial Archeology. 25. 1999. JSTOR i40043493. "Documenting Complexity: The Historic American Engineering Record and America's Technological History". IA, The Journal of the Society for Industrial Archeology.
23. 1997. JSTOR i4004348. Lindley, John; the Georgia Collection: Historic American Buildings Survey. University of Georgia Press. ISBN 0-8203-0613-4. Witcher, T. R.. "Fifty Years of Preservation: The Historic American Engineering Record". Civil Engineering. National Park Service−NPS: official Heritage Documentation Programs website
A cistern is a waterproof receptacle for holding liquids water. Cisterns are built to catch and store rainwater. Cisterns are distinguished from wells by their waterproof linings. Modern cisterns range in capacity from a few litres to thousands of cubic metres forming covered reservoirs. Waterproof lime plaster cisterns in the floors of houses are features of Neolithic village sites of the Levant at, for instance and Lebwe, by the late fourth millennium BC, as at Jawa in northeastern Lebanon, cisterns are essential elements of emerging water management techniques in dry-land farming communities. In the Middle Ages, cisterns were constructed in hill castles in Europe where wells could not be dug enough. There were two types: the filter cistern; such a filter cistern was built at the Riegersburg in Austrian Styria, where a cistern was hewn out of the lava rock. Rain water collected in the cistern; the filter enriched it with minerals. Cisterns are prevalent in areas where water is scarce, either because it is rare or has been depleted due to heavy use.
The water was used for many purposes including cooking and washing. Present-day cisterns are used only for irrigation due to concerns over water quality. Cisterns today can be outfitted with filters or other water purification methods when the water is intended for consumption, it is not uncommon for a cistern to be open in some manner in order to catch rain or to include more elaborate rainwater harvesting systems. It is important in these cases to have a system that does not leave the water open to algae or to mosquitoes, which are attracted to the water and potentially carry disease to nearby humans; some cisterns sit on the top of houses or on the ground higher than the house, supply the running water needs for the house. They are supplied not by rainwater harvesting, but by wells with electric pumps, or are filled manually or by truck delivery. Common throughout Brazil, for example, they were traditionally made of concrete walls, with a similar concrete top, with a piece that can be removed for water filling and reinserted to keep out debris and insects.
Modern cisterns are manufactured of plastic. These cisterns differ from water tanks in the sense that they are not enclosed and sealed with one form, rather they have a lid made of the same material as the cistern, removable by the user. To keep a clean water supply, the cistern must be kept clean, it is important to inspect them keep them well enclosed, to empty and clean them with a proper dilution of chlorine and to rinse them well. Well water must be inspected for contaminants coming from the ground source. City water has up to 1ppm chlorine added to the water to keep it clean, in many areas can be ordered to be delivered directly to the cistern by truck. If there is any question about the water supply at any point the cistern water should not be used for drinking or cooking. If it is of acceptable quality and consistency it can be used for toilets, housecleaning. Water of non-acceptable quality for the aforementioned uses may still be used for irrigation. If it is free of particulates but not low enough in bacteria boiling may be an effective method to prepare the water for drinking.
Many greenhouses rely on a cistern to help meet their water needs in the United States. Some countries or regions, such as Bermuda and the U. S. Virgin Islands, have strict laws requiring that rainwater harvesting systems be built alongside any new construction, cisterns can be used in these cases. Other countries, such as Japan and Spain offer financial incentives or tax credit for installing cisterns. Cisterns may be used to store water for firefighting in areas where there is an inadequate water supply; the city of San Francisco, maintains fire cisterns under its streets in case the primary water supply is disrupted. In many flat areas the use of cisterns is encouraged to absorb excess rainwater which otherwise can overload sewage or drainage systems by heavy rains. In some southeast Asian countries such as Malaysia and Indonesia showers are traditionally taken by pouring water over one's body with a dipper. Many bathrooms in modern houses are constructed with a small cistern to hold water for bathing by this method.
The modern water closet or toilet utilises a cistern to reserve and hold the correct amount of water required to flush the toilet bowl. In earlier toilets, the cistern was located high above the toilet bowl and connected to it by a long pipe, it was necessary to pull a hanging chain connected to a release valve located inside the cistern in order to flush the toilet. Modern toilets may be close coupled, with the cistern mounted directly on the toilet bowl and no intermediate pipe. In this arrangement, the flush mechanism is mounted on the cistern. Concealed cistern toilets, where the cistern is built into the wall behind the toilet, ar
In military organizations, an artillery battery is a unit of artillery, rocket artillery, multiple rocket launchers, surface to surface missiles, ballistic missiles, cruise missiles etc. so grouped to facilitate better battlefield communication and command and control, as well as to provide dispersion for its constituent gunnery crews and their systems. The term is used in a naval context to describe groups of guns on warships. Artillery battery origins from a Grand Duchy of Lithuania bajoras and artillery expert Kazimieras Simonavičius' book Artis Magnae Artilleriae published in 1650, which contains a large chapter on caliber, construction and properties of rockets, including multistage rockets, batteries of rockets, rockets with delta wing stabilizers; the term "battery" referred to a cluster of cannon in action as a group, either in a temporary field position during a battle or at the siege of a fortress or a city. Such batteries could be a mixture of howitzer, or mortar types. A siege could involve many batteries at different sites around the besieged place.
The term came to be used for a group of cannon in a fixed fortification, for coastal or frontier defence. During the 18th century "battery" began to be used as an organizational term for a permanent unit of artillery in peace and war, although horse artillery sometimes used "troop" and fixed position artillery "company", they were organised with between six and 12 ordnance pieces including cannon and howitzers. By the late 19th century "battery" had become standard replacing company or troop. In the 20th century the term was used for the company level sub-unit of an artillery branch including field, air-defence, anti-tank and position. Artillery operated target acquisition emerged during the First World War and were grouped into batteries and have subsequently expanded to include the complete intelligence, target acquisition and reconnaissance spectrum. 20th-century firing batteries have been equipped with mortars, howitzers and missiles. During the Napoleonic Wars some armies started grouping their batteries into larger administrative and field units.
Groups of batteries combined for field combat employment called Grand Batteries by Napoleon. Administratively batteries were grouped in battalions, regiments or squadrons and these developed into tactical organisations; these were further grouped into regiments "group" or brigades, that may be wholly composed of artillery units or combined arms in composition. To further concentrate fire of individual batteries, from World War I they were grouped into "artillery divisions" in a few armies. Coastal artillery sometimes had different organizational terms based on shore defence sector areas. Batteries have sub-divisions, which vary across armies and periods but translate into the English "platoon" or "troop" with individual ordnance systems called a "section" or "sub-section", where a section comprises two artillery pieces; the rank of a battery commander has varied, but is a lieutenant, captain, or major. The number of guns, mortars or launchers in an organizational battery has varied, with the calibre of guns being an important consideration.
In the 19th century four to 12 guns was usual as the optimum number to maneuver into the gun line. By the late 19th century the mountain artillery battery was divided into a gun line and an ammunition line; the gun line consisted of 12 ammunition mules. During the American Civil War, artillery batteries consisted of six field pieces for the Union Army and four for the Confederate States Army, although this varied. Batteries were divided into sections of two guns apiece, each section under the command of a lieutenant; the full battery was commanded by a captain. As the war progressed, individual batteries were grouped into battalions under a major or colonel of artillery. In the 20th century it varied between four and 12 for field artillery, or two pieces for heavy pieces. Other types of artillery such as anti-tank or anti-aircraft have sometimes been larger; some batteries have been "dual-equipped" with two different types of gun or mortar, taking whichever was more appropriate when they deployed for operations.
From the late 19th century field artillery batteries started to become more complex organisations. First they needed the capability to carry adequate ammunition each gun could only carry about 40 rounds in its limber so additional wagons were added to the battery about two per gun; the introduction on indirect fire in the early 20th century necessitated two other groups, firstly observers who deployed some distance forward of the gun line, secondly a small staff on the gun position to undertake the calculations to convert the orders from the observers into data that could be set on the gun sights. This in turn led to the need for signalers, which further increased as the need to concentrate the fire of dispersed batteries emerged and the introduction fire control staff at artillery headquarters above the batteries. Fixed artillery refers to guns or howitzers on mounts that were either anchored in one spot, or on carriages intended to be moved only for the purposes of aiming, not for tactical repositioning.
Historical versions closely resembled naval cannon of their day, "garrison carriages," like naval carriages, were short and had four small wheels meant for rolling on
San Juan, Puerto Rico
San Juan is the capital and most populous municipality in the Commonwealth of Puerto Rico, an unincorporated territory of the United States. As of the 2010 census, it is the 46th-largest city under the jurisdiction of the United States, with a population of 395,326. San Juan was founded by Spanish colonists in 1521. Puerto Rico's capital is the third oldest European-established capital city in the Americas, after Santo Domingo, in the Dominican Republic, founded in 1496 and Panama City, in Panama, founded in 1519. Several historical buildings are located in San Juan. Today, San Juan is Puerto Rico's most important seaport and is the island's manufacturing, financial and tourism center; the population of the Metropolitan Statistical Area, including San Juan and the municipalities of Bayamón, Cataño, Canóvanas, Toa Alta, Toa Baja and Trujillo Alto, is about 2.6 million inhabitants. San Juan is a principal city of the San Juan-Caguas-Fajardo Combined Statistical Area; the city has been the host of events within the sports community, including the 1979 Pan American Games.
In 1508, Juan Ponce de León founded the original settlement. It was named after the Province of Cáceres in Spain, the birthplace of Nicolás de Ovando the Governor of Spain's Caribbean territories, Today it is part of the Pueblo Viejo sector of Guaynabo, just to the west of the present San Juan metropolitan area. A year the settlement was moved to a site called Puerto Rico, Spanish for "rich port" or "good port", after its similar geographical features to the town of Puerto Rico of Gran Canaria in the Canary Islands. In 1521, the newer settlement was given its formal name: Puerto Rico de San Juan Bautista; the ambiguous use of San Juan Bautista and Puerto Rico for both the city and the island in time led to a reversal in practical use by most inhabitants: by 1746 the name for the city had become that of the entire island, leading to the city being identified as Puerto Rico de Puerto Rico on maps of the era. San Juan, as a settlement of the Spanish Empire, was used by merchant and military ships traveling from Spain as the first stopover in the Americas.
Because of its prominence in the Caribbean, a network of fortifications was built to protect the transports of gold and silver from the New World to Europe. Because of the rich cargoes, San Juan became a target of the foreign powers of the time; the city was witness to attacks from the English led by Sir Francis Drake in 1595 and by George Clifford, Earl of Cumberland, in 1598. Artillery from San Juan's fort, El Morro, repelled Drake. After a few months of English occupation, Clifford was forced to abandon the siege when his troops began to suffer from exhaustion and sickness. In 1625 the city was sacked by Dutch forces led by Captain Balduino Enrico, but El Morro withstood the assault and was not taken; the Dutch were counterattacked by Captain Juan de Amézqueta and 50 members of the civilian militia on land and by the cannons of the Spanish troops in El Morro Castle. The land battle left 60 Dutch soldiers dead and Enrico with a sword wound to his neck which he received from the hands of Amézqueta.
The Dutch ships at sea were boarded by Puerto Ricans. After a long battle, the Spanish soldiers and volunteers of the city's militia were able to defend the city from the attack and save the island from an invasion. On October 21, Enrico set the city ablaze. Captains Amézqueta and Andrés Botello decided to put a stop to the destruction and led 200 men in an attack against the enemy's front and rear guard, they drove Enrico and his men from their trenches and into the ocean in their haste to reach their ships. The British attack in 1797, during the French Revolutionary Wars, led by Sir Ralph Abercromby, his army laid siege to the city but was forced to withdraw in defeat as the Puerto Rican defenses proved more resilient than those of Trinidad. Various events and circumstances, including liberalized commerce with Spain, the opening of the island to immigrants as a direct result of the Royal Decree of Graces of 1815, the colonial revolutions, led to an expansion of San Juan and other Puerto Rican settlements in the late 18th and early 19th century.
On May 8, 1898, United States Navy ships, among them the USS Detroit, USS Indiana, USS New York, USS Amphitrite, USS Terror and USS Montgomery, commanded by Rear Admiral William T. Sampson arrived at San Juan Bay; the USS Yale captured a Spanish freighter, the Rita in San Juan Bay, thus being the first hostile encounter between the warring sides in Puerto Rico. On May 9, Yale fought a brief battle with an auxiliary cruiser of Spain, name unknown, resulting in a Spanish victory. Around this time, Captain Ángel Rivero Méndez was assigned the command of the Spanish forces in the fortress of San Cristóbal in San Juan. On May 10, the Yale returned to San Juan Bay, Rivero-Méndez ordered his men to open fire upon the USS Yale using an Ordoñez 15 centimeter cannon, thus becoming the first attack against the Americans in Puerto Rico during the Spanis
A casemate is a fortified gun emplacement or armored structure from which guns are fired. The term referred to a vaulted chamber in a fortress. In armoured fighting vehicles that do not have a turret for the main gun, the structure that accommodates the gun is termed the casemate; the word comes from the Italian casamatta, the etymology of, uncertain, though it could derive from casa, matta, "done with reeds and wickers", thus a low-roof hut without windows or other openings set in marshy place. It could derive from casa matta with matta in the sense of "false". A casemate was a vaulted chamber constructed underneath the rampart, it could be used for sheltering troops or stores. With the addition of an embrasure through the scarp face of the rampart, it could be used as a protected gun position. In the early 19th century, French military engineer Baron Haxo designed a free-standing casemate that could be built on the top of the rampart. Casemates built in concrete were used in the Second World War to protect coastal artillery from air attack.
In warship design the term "casemate" has been used in a number of ways. The American Civil War saw the use of casemate ironclads: armored steamboats with a low freeboard and their guns on the main deck protected by a sloped armoured casemate, which sat on top of the hull. Although both sides of the Civil War used casemate ironclads, the ship is associated with the southern Confederacy, as the north employed turreted monitors, which the south was unable to produce; the most famous naval battle of the war was the duel at Hampton Roads between the Union turretted ironclad USS Monitor and the Confederate casemate ironclad CSS Virginia. "Casemate ship" was an alternative term for "central battery ship" or "center battery ship". The casemate was an armoured box; the armoured sides of the box were the sides of hull of the ship. There was an armoured bulkhead at the front and rear of the casemate, a thick deck protecting the top; the lower edge of the casemate sat on top of ship's belt armour. Some ships, such as the Alexandra, had a two-storey casemate.
A "casemate" was an armoured room in the side of a warship. A typical casemate held a 6-in gun, had a 6" front plate, with thinner armour plates on the sides and rear, with a protected top and floor, weighed about 20 tons. Casemates were similar in size to turrets; the first battleships to carry them were the British Royal Sovereign class laid down in 1889. They were adopted as a result of live-firing trials against HMS Resistance in 1888. Casemates were adopted because it was thought that the fixed armour plate at the front would provide better protection than a turret, because a turret mounting would require external power and could therefore be put out of action if power were lost – unlike a casemate gun, which could be worked by hand; the use of casemates enabled the 6-in guns to be dispersed, so that a single hit would not knock out all of them. Casemates were used in protected and armoured cruisers, starting with the 1889 Edgar class, and retrofitted to the 1888 Blake class during construction.
In the pre-dreadnought generation of warships, casemates were placed on the main deck, on the upper deck as well. Casemates on the main deck were close to the waterline. In the Edgar-class cruisers, the guns in the casemates were only 10 feet above the waterline. Casemates that were too close to the waterline or too close to the bow were prone to flooding, making the guns ineffective. Shipboard casemate guns were rendered obsolete by the arrival of “all-big gun” battleship, pioneered by HMS ‘’Dreadnought’’ in 1906, but were reintroduced as the increasing torpedo threat from destroyers forced an increase in secondary armament calibre. Many battleships had their casemates plated over during modernization in the 1930s but some, like HMS Warspite carried them to the end of WWII; the last ships built with casemates as new construction were the American Omaha class cruisers of the early 1920s and the 1933 Swedish aircraft cruiser Gotland. In both cases the casemates were built into the forward angles of the forward superstructure.
In regards to armoured fighting vehicles, casemate design refers to vehicles that have their main gun mounted directly within the hull and lack the rotating turret associated with tanks. Such a design makes the vehicle mechanically simpler in design, less costly in construction, lighter in weight and lower in profile; the saved weight can be used to mount a heavier, more powerful gun or alternatively increase the vehicle's armour protection in comparison to regular, turreted tanks. However, in combat the crew has to rotate the entire vehicle if an enemy target presents itself outside of the vehicle's limited gun traverse arc; this can prove disadvantageous in combat situations. During World War II, casemate-type armoured fighting vehicles were used by both the German Wehrmacht and the Soviet Red Army, they were employed as tank destroyers and assault guns. Tank destroyers, intended to operate from defensive ambush operations, did not need a rotating turret as much as offensively used tanks, while assault guns were used against fo
A bastion or bulwark is a structure projecting outward from the curtain wall of a fortification, most angular in shape and positioned at the corners. The developed bastion consists of two faces and two flanks with fire from the flanks being able to protect the curtain wall and the adjacent bastions, it is one element in the style of fortification dominant from the mid 16th to mid 19th centuries. Bastion fortifications offered a greater degree of passive resistance and more scope for ranged defense in the age of gunpowder artillery compared with the medieval fortifications they replaced. By the middle of the 15th century, artillery pieces had become powerful enough to make the traditional medieval round tower and curtain wall obsolete; this was exemplified by the campaigns of Charles VII of France who reduced the towns and castles held by the English during the latter stages of the Hundred Years War, by the fall of Constantinople in 1453 to the large cannon of the Turkish army. During the Eighty Years War Dutch military engineers developed the concepts further lengthening the faces and shortening the curtain walls of the bastions.
The resulting construction was called a bolwerk. To augment this change they placed v-shaped outworks known as ravelins in front of the bastions and curtain walls to protect them from direct artillery fire; these ideas were further developed and incorporated into the trace italienne forts by Sébastien Le Prestre de Vauban, that remained in use during the Napoleonic Wars. Bastions differ from medieval towers in a number of respects. Bastions are lower than towers and are of similar height to the adjacent curtain wall; the height of towers, although making them difficult to scale made them easy for artillery to destroy. A bastion would have a ditch in front, the opposite side of which would be built up above the natural level slope away gradually; this glacis shielded most of the bastion from the attacker's cannon while the distance from the base of the ditch to the top of the bastion meant it was still difficult to scale. In contrast to typical late medieval towers, bastions were flat sided rather than curved.
This eliminated dead ground making it possible for the defenders to fire upon any point directly in front of the bastion. Bastions cover a larger area than most towers; this allows more cannons to be provided enough space for the crews to operate them. Surviving examples of bastions are faced with masonry. Unlike the wall of a tower this was just a retaining wall; the top of the bastion was exposed to enemy fire, would not be faced with masonry as cannonballs hitting the surface would scatter lethal stone shards among the defenders. If a bastion was stormed, it could provide the attackers with a stronghold from which to launch further attacks; some bastion designs attempted to minimise this problem. This could be achieved by the use of retrenchments in which a trench was dug across the rear of the bastion, isolating it from the main rampart. Various kinds of bastions have been used throughout history. Solid bastions are those that are filled up and have the ground with the height of the rampart, without any empty space towards the centre.
Void or hollow bastions are those that have a rampart, or parapet, only around their flanks and faces, so that a void space is left towards the centre. The ground is so low, that if the rampart is taken, no retrenchment can be made in the centre, but what will lie under the fire of the besieged. A flat bastion is one built in the middle of a curtain, or enclosed court, when the court is too large to be defended by the bastions at its extremes. A cut bastion is that, it was sometimes called bastion with a tenaille. Such bastions were used; the term cut bastion is used for one, cut off from the place by some ditch. A composed bastion is when the two sides of the interior polygon are unequal, which makes the gorges unequal. A regular bastion is that which has proportionate faces and gorges. A deformed or irregular bastion is one. A demi-bastion has flank. To fortify the angle of a place, too acute, they cut the point, place two demi-bastions, which make a tenaille, or re-entry angle, their chief use is before a crownwork.
A double bastion is that which on the plain of the great bastion has another bastion built higher, leaving 4–6 m between the parapet of the lower and the base of the higher. Semi-circular bastions were used in the 16th century, but fell out of favour because of the difficulty of concentrating the fire of guns distributed around a curve. Known as "half-moon" bastions. Circular bastions or roundels evolved in the 15th and early 16th centuries but were superseded by angled bastions. Bastille Battery tower Roundel Whitelaw, A. ed. The popular encyclopedia. P&G, pp. 50–54, ISBN 978-1-906394-07-3 Nossov, Konstantin. H. (19
A battlement in defensive architecture, such as that of city walls or castles, comprises a parapet, in which gaps or indentations, which are rectangular, occur at intervals to allow for the launch of arrows or other projectiles from within the defences. These gaps are termed "crenels", the act of adding crenels to a unbroken parapet is termed crenellation. A defensive building might be designed and built with battlements, or a manor house might be fortified by adding battlements, where no parapet existed, or cutting crenellations into its existing parapet wall; the solid widths between the crenels are called merlons. A wall with battlements is said to be embattled. Battlements on walls have protected walkways behind them. On tower or building tops, the roof is used as the protected fighting platform; the term originated in about the 14th century from the Old French word batailler, "to fortify with batailles". The word crenel derives from the ancient French cren, Latin crena, meaning a notch, mortice or other gap cut out to receive another element or fixing.
The modern French word for crenel is créneau used to describe a gap of any kind, for example a parking space at the side of the road between two cars, interval between groups of marching troops or a timeslot in a broadcast. In medieval England and Wales a licence to crenellate granted the holder permission to fortify their property; such licences were granted by the king, by the rulers of the counties palatine within their jurisdictions, e.g. by the Bishops of Durham and the Earls of Chester and after 1351 by the Dukes of Lancaster. The castles in England vastly outnumber the licences to crenellate Royal pardons were obtainable, on the payment of an arbitrarily determined fine, by a person who had fortified without licence; the surviving records of such licences issued by letters patent, provide valuable evidence for the dating of ancient buildings. A list of licences issued by the English Crown between the 12th and 16th centuries was compiled by Turner & Parker and expanded and corrected by Philip Davis and published in The Castle Studies Group Journal.
There has been academic debate over the purpose of licensing. The view of military-focused historians is that licensing restricted the number of fortifications that could be used against a royal army; the modern view, proposed notably by Charles Coulson, is that battlements became an architectural status-symbol much sought after by the ambitious, in Coulson's words: "Licences to crenellate were symbolic representations of lordly status: castellation was the architectural expression of noble rank". They indicated to the observer that the grantee had obtained "royal recognition and compliment", they could however provide a basic deterrent against wandering bands of thieves, it is suggested that the function of battlements was comparable to the modern practice of householders fitting visible CC-TV and burglar alarms merely dummies. The crown did not charge for the granting of such licences, but charged a fee of about half a mark. Battlements may be stepped out to overhang the wall below, may have openings at their bases between the supporting corbels, through which stones or burning objects could be dropped onto attackers or besiegers.
Battlements have been used for thousands of years. Battlements were used in the walls surrounding Assyrian towns, as shown on bas reliefs from Nimrud and elsewhere. Traces of them remain at Mycenae in Greece, some ancient Greek vases suggest the existence of battlements; the Great Wall of China has battlements. In the European battlements of the Middle Ages the crenel comprised one-third of the width of the merlon: the latter, in addition, could be provided with arrow-loops of various shapes, depending on the weapon being utilized. Late merlons permitted fire from the first firearms. From the 13th century, the merlons could be connected with wooden shutters that provided added protection when closed; the shutters were designed to be opened to allow shooters to fire against the attackers, closed during reloading. The Romans used low wooden pinnacles for their first aggeres. In the battlements of Pompeii, additional protection derived from small internal buttresses or spur walls, against which the defender might stand so as to gain complete protection on one side.
Loop-holes were frequent in Italian battlements, where the merlon has much greater height and a distinctive cap. Italian military architects used the so-called Ghibelline or swallowtail battlement, with V-shaped notches in the tops of the merlon, giving a horn-like effect; this would allow the defender to be protected whilst shooting standing upright. The normal rectangular merlons were nicknamed Guelph. In Muslim and African fortifications, the merlons were rounded; the battlements of the Arabs had a more decorative and varied character, were continued from the 13th century onwards not so much for defensive purposes as for a crowning feature to the walls. They serve a function similar to the cresting found in the Spanish Renaissance. "Irish" crenellations are a distinctive form that appeared in Ireland between the 14th and 17th centuries. These were battlements of a "stepped" form, with each merlon shaped like an inverted'T'. European architects persistently used battlements as a purely decorative feature throughout the Decorated and Perpendicular periods of Gothi