The Pont Saint-Bénézet known as the Pont d'Avignon, is a famous medieval bridge in the town of Avignon, in southern France. A wooden bridge spanning the Rhône between Villeneuve-lès-Avignon and Avignon was built between 1177 and 1185; this early bridge was destroyed forty years during the Albigensian Crusade when Louis VIII of France laid siege to Avignon. Beginning in 1234 the bridge was rebuilt with 22 stone arches, it was abandoned in the mid-17th century as the arches tended to collapse each time the Rhône flooded making it expensive to maintain. Four arches and the gatehouse at the Avignon end of the bridge have survived; the Chapel of Saint Nicholas sits on the second pier of the bridge. It was constructed in the second half of 12th century but has since been altered; the western terminus, the Tour Philippe-le-Bel, is preserved. The bridge was the inspiration for the song Sur le pont d'Avignon and is considered a landmark of the city. In 1995, the surviving arches of the bridge, together with the Palais des Papes and Cathédrale Notre-Dame des Doms were classified as a World Heritage Site.
The bridge spanned the Rhône between Villeneuve-lès-Avignon. The first bridge was built with an length of some 900 m, it was destroyed during the siege of Avignon by Louis VIII of France in 1226 but beginning in 1234 it was rebuilt. Historians have suggested that the first bridge would have been either constructed of wood or may have been a wooden superstructure supported on stone piers. Only when rebuilt was the bridge constructed in stone; the stone bridge had 21 piers. It did not run directly between the two gatehouses, but instead followed a curved path an adaption to the position of the islands when it was first built. Over the centuries the Rhône has shifted across its floodplain; the position of the islands in the 13th century is not well documented but a 17th century map shows that the southern end of the Île de la Barthelasse was upstream of the bridge. The bridge crossed small islands; the spacing between the piers varied between 52 m. The bridge was only 4.9 m including the parapets at the sides.
The arches were liable to collapse when the river flooded and were sometimes replaced with temporary wooden structures before being rebuilt in stone. The bridge fell into a state of disrepair during the 17th century. By 1644 the bridge was missing four arches, a flood in 1669 swept away more of the structure. Since its surviving arches have successively collapsed or been demolished, only four of the arches remain; the only other visible vestige of the bridge is some masonry from pier 11, attached to a private building on the Île de la Barthelasse. Remains of other piers are buried under a thick layer of sediment on the island or at the bottom of the Rhône; the locations of piers 9 and 10, both now on the Île de la Barthelasse, were confirmed by cores drilled at their expected positions. Masonry from the piers was reached at a depth of 3 m below ground level. Just below the masonry, at a depth of around 6.7 m, wooden fragments, identified as silver fir, were recovered. Carbon-14 dating of this material gave dates of 1238–1301 AD for pier 9 and 1213–1280 AD for pier 10.
The arches are segmental rather than the semi-circular shape used in Roman bridges. Of the remaining arches the largest span is 35.8 m between the fourth piers. The piers have cutwaters that are pointed both downstream; these reduce the scour around one of the main threats to the stability of stone bridges. The piers were constructed with openings in the stone work to reduce the pressure from the flow of water when river was in flood. With the collapse of the Saint-Bénézet bridge the Rhône at Avignon was crossed by ferry until the beginning of the 19th century. Between 1806 and 1818 a wooden bridge was built across the two branches of the river; the section across the Avignon branch was replaced by a suspension bridge in 1843. This was demolished in 1960 with the opening of the Edouard Daladier bridge; the section across the Villeneuve branch of the Rhône was not replaced until 1909. The replacement stone bridge, the Nouveau Pont, was damaged by bombing in 1944, it was repaired after the war but was replaced by the Pont du Royaume in 1972.
The bridge's construction was inspired by Saint Bénézet, a shepherd boy from the hamlet of Villard in the Ardèche, who while tending his flock heard the voice of Jesus Christ asking him to build a bridge across the river. Although he was ridiculed at first, he "proved" his divine inspiration by miraculously lifting a huge block of stone, he formed a Bridge Brotherhood to oversee its construction. After his death, he was interred on the bridge itself, in a small chapel standing on one of the bridge's surviving piers on the Avignon side; the Saint Nicholas Chapel sits on a platform on the upstream side of the second pier. The bridge chapel has undergone several phases of restoration, it is now divided into each with a nave and an apse. The upper floor is on a level with the platform of the bridge and reduces the width of the walkway to 1.75 m. The lower floor is accessed by a set of steps; the exterior of the chapel shows evidence of the rebuilding work with blocked windows on the south-eastern wall.
The nave is covered with stone roof tiles. The polygonal apse has a flat roo
Tanning is the process of treating skins and hides of animals to produce leather. A tannery is the place. Tanning hide into leather involves a process which permanently alters the protein structure of skin, making it more durable and less susceptible to decomposition, possibly coloring it. Before tanning, the skins are unhaired, degreased and soaked in water over a period of 6 hours to 2 days; this process was considered a noxious or "odoriferous trade" and relegated to the outskirts of town. Traditionally, tanning used tannin, an acidic chemical compound from which the tanning process draws its name; the use of a chromium solution was adopted by tanners in the Industrial Revolution. The English word for tanning is from medieval Latin tannāre, deriv. of tannum, from French tan, from old-Cornish tann. These terms are related to a hypothetical dʰonu meaning fir tree in Proto-Indo-European.. Despite the linguistic confusion between quite different conifers and oaks, the word tan referring to dyes and types of hide preservation is from the Gaulic use referencing the bark of oaks, not fir trees.
Ancient civilizations used leather for waterskins, bags and tack, armour, scabbards and sandals. Tanning was being carried out by the inhabitants of Mehrgarh in Pakistan between 7000 and 3300 BC. Around 2500 BC, the Sumerians began using leather, affixed by copper studs, on chariot wheels. Tanning was considered a noxious or "odoriferous trade" and relegated to the outskirts of town, amongst the poor. Indeed, tanning by ancient methods is so foul smelling, tanneries are still isolated from those towns today where the old methods are used. Skins arrived at the tannery dried stiff and dirty with soil and gore. First, the ancient tanners would soak the skins in water to soften them, they would pound and scour the skin to remove any remaining flesh and fat. Next, the tanner needed to remove the hair from the skin; this was done by either soaking the skin in urine, painting it with an alkaline lime mixture, or allowing the skin to putrefy for several months dipping it in a salt solution. After the hairs were loosened, the tanners scraped them off with a knife.
Once the hair was removed, the tanners would "bate" the material by pounding dung into the skin, or soaking the skin in a solution of animal brains. Bating was a fermentative process. Among the kinds of dung used were those of dogs or pigeons; the actual tanning process used vegetable tanning. In some variations of the process, cedar oil, alum, or tannin were applied to the skin as a tanning agent; as the skin was stretched, it would absorb the agent. Following the adoption in medicine of soaking gut sutures in a chromium solution after 1840, it was discovered that this method could be used with leather and thus was adopted by tanners; the tanning process begins with obtaining an animal skin. When an animal skin is to be tanned, the animal is killed and skinned before the body heat leaves the tissues; this can be done by the tanner, or by obtaining a skin at a slaughterhouse, farm, or local fur trader. Preparing hides begins by curing them with salt. Curing is employed to prevent putrefaction of the protein substance from bacterial growth during the time lag from procuring the hide to when it is processed.
Curing removes water from the skins using a difference in osmotic pressure. The moisture content of hides and skins is reduced, osmotic pressure increased, to the point that bacteria are unable to grow. In wet-salting, the hides are salted pressed into packs for about 30 days. In brine-curing, the hides are agitated in a saltwater bath for about 16 hours. Curing can be accomplished by preserving the hides and skins at low temperatures; the steps in the production of leather between curing and tanning are collectively referred to as beamhouse operations. They include, in order, liming, removal of extraneous tissues, bating or puering and pickling. In soaking, the hides are soaked in clean water to remove the salt left over from curing and increase the moisture so that the hide or skin can be further treated. To prevent damage of the skin by bacterial growth during the soaking period, biocides dithiocarbamates, may be used. Fungicides such as 2-thiocyanomethylthiobenzothiazole may be added in the process, to protect wet leathers from mold growth.
After 1980, the use of pentachlorophenol and mercury-based biocides and their derivatives was forbidden. After soaking, the hides and skins are taken for liming: treatment with milk of lime that may involve the addition of "sharpening agents" such as sodium sulfide, amines, etc; the objectives of this operation are to: Remove the hair and other keratinous matter Remove some of the interfibrillary soluble proteins such as mucins Swell up and split up the fibres to the desired extent Remove the natural grease and fats to some extent Bring the collagen in the hide to a proper condition for satisfactory tannageThe weakening of hair is dependent on the breakdown of the disulfide link of the amino acid cystine, the characteristic of the keratin class of proteins that gives strength to hair and wools. The hydrogen
Sir Nikolaus Bernhard Leon Pevsner was a German British scholar of the history of art of architecture. Pevsner is best known for his monumental 46-volume series of county-by-county guides, The Buildings of England simply referred to by his surname. Nikolaus Pevsner was born in Leipzig, the son of Hugo Pevsner, a Russian-Jewish fur merchant, his wife, Anna, he attended St. Thomas School and went on to study at several universities, Munich and Frankfurt am Main, before being awarded a doctorate by Leipzig in 1924 for a thesis on the Baroque architecture of Leipzig. In 1923, he married the daughter of distinguished Leipzig lawyer, Alfred Kurlbaum, he worked as an assistant keeper at the Dresden Gallery. He converted to Lutheranism early in life. During this period he became interested in establishing the supremacy of German modernist architecture after becoming aware of Le Corbusier's Pavillon de l'Esprit Nouveau at the Paris Exhibition of 1925. In 1928 he contributed the volume on Italian baroque painting to the Handbuch der Kunstwissenschaft, a multi-volume series providing an overview of the history of European art.
He taught at the University of Göttingen, offering a specialist course on English art and architecture. According to biographer Stephen Games, Pevsner welcomed many of the economic and cultural policies of the early Hitler regime. However, due to Nazi race laws he was forced to resign his lectureship in 1933; that year Pevsner moved to England, settling in Hampstead, where poet Geoffrey Grigson was his neighbour in Wildwood Terrace. Pevsner's first post was an 18-month research fellowship at the University of Birmingham, found for him by friends in Birmingham and funded by the Academic Assistance Council. A study of the role of the designer in the industrial process, the research produced a critical account of design standards in Britain which he published as An Enquiry into Industrial Art in England, he was subsequently employed as a buyer of modern textiles and ceramics for the Gordon Russell furniture showrooms in London. By this time Pevsner had completed Pioneers of the Modern Movement: from William Morris to Walter Gropius, his influential pre-history of what he saw as Walter Gropius's dominance of contemporary design.
Pioneers ardently championed Gropius's first two buildings on the grounds that they summed up all the essential goals of 20th-century architecture. In spite of that, the book remains an important point of reference in the teaching of the history of modern design, helped lay the foundation of Pevsner's career in England as an architectural historian. Since its first publication by Faber & Faber in 1936, it has gone through several editions and been translated into many languages; the English-language edition has been renamed Pioneers of Modern Design. Pevsner was "more German than the Germans" to the extent that he supported "Goebbels in his drive for'pure' non-decadent German art", he was reported as saying of the Nazis: "I want this movement to succeed. There is no alternative but chaos.... There are things worse than Hitlerism." Nonetheless, he was included in the Nazi Black Book as hostile to the Hitler regime. In 1940, Pevsner was taken to the internment camp at Liverpool, as an enemy alien.
Geoffrey Grigson wrote in his Recollections: "When at last two hard-faced Bow Street runners arrived in the early hours of the morning to take... I managed, clutching my pyjama trousers, to catch them up with the best parting present I could think of, an elegant little edition, a new edition, of Shakespeare's Sonnets." Pevsner was released after three months on the intervention of, among others, Frank Pick Director-General of the Ministry of Information. He spent some time in the months after the Blitz clearing bomb debris, wrote reviews and art criticism for the Ministry of Information's Die Zeitung, an anti-Nazi publication for Germans living in England, he completed for Penguin Books the Pelican paperback An Outline of European Architecture, which he had begun to develop while in internment. Outline would go into seven editions, be translated into 16 languages, sell more than half a million copies. In 1942, Pevsner secured two regular positions. From 1936 onwards he had been a frequent contributor to the Architectural Review and from 1943 to 1945 he stood in as its acting editor while the regular editor J. M. Richards was on active service.
Under the AR's influence, Pevsner's approach to modern architecture became more complex and more moderate. Early signs of a lifelong interest in Victorian architecture influenced by the Architectural Review, appeared in a series written under the pseudonym of "Peter F. R. Donner": Pevsner's "Treasure Hunts" guided readers down selected London streets, pointing out architectural treasures of the 19th century, he was closely involved with the Review's proprietor, H. de C. Hastings, in evolving the magazine's theories on picturesque planning. In 1942, Pevsner was appointed a part-time lecturer at Birkbeck College, London, he lectured at Cambridge University for 30 years, having been Slade professor there for a record six years from 1949 to 1955, would become the Slade professorship at Oxford in 1968. Framing all this was his career as a writer and editor. After moving to England, Pevsn
Exeter is a cathedral city in Devon, with a population of 129,800. The city is located on the River Exe 36 miles northeast of Plymouth and 65 miles southwest of Bristol, it is the county town of Devon, the base of Devon County Council. Situated in Exeter, are two campuses of the University of Exeter, Streatham Campus and St Luke's Campus. In Roman Britain, Exeter was established as the base of Legio II Augusta under the personal command of Vespasian. Exeter became a religious centre during the Middle Ages and into the Tudor times: Exeter Cathedral, founded in the mid 11th century, became Anglican during the 16th-century English Reformation. During the late 19th century, Exeter became an affluent centre for the wool trade, although by the First World War the city was in decline. After the Second World War, much of the city centre was rebuilt and is now considered to be a centre for modern business and tourism in Devon and Cornwall; the administrative area of Exeter has the status of a non-metropolitan district under the administration of the County Council.
The modern name of Exeter is a development of the Old English Escanceaster, from the anglicised form of the river now known as the Exe and the Old English suffix -ceaster, used to mark important fortresses or fortified towns. The name "Exe" is a separate development of the Brittonic name—meaning "water" or, more "full of fish" —that appears in the English Axe and Esk and the Welsh Usk. Exeter began as settlements on a dry ridge ending in a spur overlooking a navigable river teeming with fish, with fertile land nearby. Although there have been no major prehistoric finds, these advantages suggest the site was occupied early. Coins have been discovered from the Hellenistic kingdoms, suggesting the existence of a settlement trading with the Mediterranean as early as 250 BC; such early towns had been a feature of pre-Roman Gaul as described by Julius Caesar in his Commentaries and it is possible that they existed in Britannia as well. The Romans established a 42-acre'playing-card' shaped fort named Isca around AD 55.
The fort was the southwest terminus of the Fosse Way and served as the base of the 5 000-man Second Augustan Legion led by Vespasian Roman Emperor, for the next 20 years before they moved to Caerleon in Wales, known as Isca. To distinguish the two, the Romans referred to Exeter as Isca Dumnoniorum, "Watertown of the Dumnonii", Caerleon as Isca Augusta. A small fort was maintained at Topsham; the presence of the fort built up an unplanned civilian community of natives and the soldiers' families to the northeast of the fort. This settlement served as the tribal capital of the Dumnonii and was listed as one of their four cities by Ptolemy in his Geography; when the fortress was abandoned around the year 75, its grounds were converted to civilian purposes: its large bathhouse was demolished to make way for a forum and a basilica, a smaller-scale bath was erected to the southeast. This area was excavated in the 1970s, but could not be maintained for public view owing to its proximity to the present-day cathedral.
In January 2015, it was announced that Exeter Cathedral had launched a bid to restore the baths and open an underground centre for visitors. In the late 2nd century, the ditch and rampart defences around the old fortress were replaced by a bank and wall enclosing a much larger area, some 92 acres. Although most of the visible structure is older, the course of the Roman wall was used for Exeter's subsequent city walls, thus about 70% of the Roman wall remains, most of its route can be traced on foot. The Devonian Isca seems to have been most prosperous in the first half of the 4th century: more than a thousand Roman coins have been found around the city and there is evidence for copper and bronze working, a stock-yard, markets for the livestock and pottery produced in the surrounding countryside; the dating of the coins so far discovered, suggests a rapid decline: none have been discovered dated after the year 380. Bishop Ussher identified the Cair Pensa vel Coyt listed among the 28 cities of Britain by the History of the Britons as Isca, although David Nash Ford read it as a reference to Penselwood and thought it more to be Lindinis.
Nothing is known of Exeter from the time of the Roman withdrawal from Britain around the year 410 until the seventh century. By that time, the city was held by the Saxons, who had arrived in Exeter after defeating the British Dumnonians at Peonnum in Somerset in 658, it seems that the Saxons maintained a quarter of the city for the Britons under their own laws around present-day Bartholomew Street, known as "Britayne" Street until 1637 in memory of its former occupants. Exeter was known to the Saxons as Escanceaster. In 876, it was attacked and captured by Danish Vikings. Alfred the Great drove them out the next summer. Over the next few years, he elevated Exeter to one of the four burhs in Devon, rebuilding its walls on the Roman lines; these permitted the city to fend off another attack and siege by the Danes in 893. Ki
Dissolution of the Monasteries
The Dissolution of the Monasteries, sometimes referred to as the Suppression of the Monasteries, was the set of administrative and legal processes between 1536 and 1541 by which Henry VIII disbanded monasteries, priories and friaries in England and Ireland, appropriated their income, disposed of their assets, provided for their former personnel and functions. Although the policy was envisaged as increasing the regular income of the Crown, much former monastic property was sold off to fund Henry's military campaigns in the 1540s, he was given the authority to do this in England and Wales by the Act of Supremacy, passed by Parliament in 1534, which made him Supreme Head of the Church in England, thus separating England from Papal authority, by the First Suppression Act and the Second Suppression Act. Professor George W. Bernard argues: The dissolution of the monasteries in the late 1530s was one of the most revolutionary events in English history. There were nearly 900 religious houses in England, around 260 for monks, 300 for regular canons, 142 nunneries and 183 friaries.
If the adult male population was 500,000, that meant that one adult man in fifty was in religious orders. At the time of their suppression, a small number of English and Welsh religious houses could trace their origins to Anglo-Saxon or Celtic foundations before the Norman Conquest, but the overwhelming majority of the 625 monastic communities dissolved by Henry VIII had developed in the wave of monastic enthusiasm that had swept western Christendom in the 11th and 12th centuries. Few English houses had been founded than the end of the 13th century. 11th- and 12th-century founders had endowed monastic houses with both'temporal' income in the form of revenues from landed estates, and'spiritual' income in the form of tithes appropriated from parish churches under the founder's patronage. In consequence of this, religious houses in the 16th century controlled appointment to about two-fifths of all parish benefices in England, disposed of about half of all ecclesiastical income, owned around a quarter of the nation's landed wealth.
An English medieval proverb said that if the Abbot of Glastonbury married the Abbess of Shaftesbury, the heir would have more land than the King of England. The 200 houses of friars in England and Wales constituted a second distinct wave of foundations all occurring in the 13th century. Friaries, for the most part, were concentrated in urban areas. Unlike monasteries, friaries had eschewed income-bearing endowments; the Dissolution of the Monasteries in England and Ireland took place in the political context of other attacks on the ecclesiastical institutions of Western Roman Catholicism, under way for some time. Many of these were related to the Protestant Reformation in Continental Europe. By the end of the 16th century, monasticism had entirely disappeared from those European states whose rulers had adopted Lutheran or Reformed confessions of faith, they continued, albeit in reduced numbers and radically changed forms, in those states that remained Catholic. But, the religious and political changes in England under Henry VIII and Edward VI were of a different nature from those taking place in Germany, France and Geneva.
Across much of continental Europe, the seizure of monastic property was associated with mass discontent among the common people and the lower level of clergy and civil society against powerful and wealthy ecclesiastical institutions. Such popular hostility against the church was rare in England before 1558; these changes were met with widespread popular suspicion. Dissatisfaction with the general state of regular religious life, with the gross extent of monastic wealth, was near to universal amongst late medieval secular and ecclesiastical rulers in the Latin West. Bernard says there was widespread concern in the 15th and early 16th centuries about the condition of the monasteries. A leading figure here is the scholar and theologian Desiderius Erasmus who satirized monasteries as lax, as comfortably worldly, as wasteful of scarce resources, as superstitious. At that time, quite a few bishops across Europe had come to believe that resources expensively deployed on an unceasing round of services by men and women in theory set apart from the world be better spent on endowing grammar schools and university colleges to train men who would serve the laity as parish priests, on reforming the antiquated structures of over-large dioceses such as that of Lincoln.
Pastoral care was seen as much more important and vital than the monastic focus on contemplation and performance of the daily office. Erasmus had made a threefold criticism of the monks and nuns of his day, saying that: in withdrawing from the world into their own communal life, they elevated man-made monastic vows of poverty and obedience above the God-given vows of sacramental
In architecture, a vault is a self-supporting arched form of stone or brick, serving to cover a space with a ceiling or roof. The simplest kind of vault is the barrel vault, semicircular in shape; the barrel vault is the length being greater than its diameter. As in building an arch, a temporary support is needed while rings of voussoirs are constructed and the rings placed in position; until the topmost voussoir, the keystone, is positioned, the vault is not self-supporting. Where timber is obtained, this temporary support is provided by centering consisting of a framed truss with a semicircular or segmental head, which supports the voussoirs until the ring of the whole arch is completed. With a barrel vault, the centering can be shifted on to support the next rings; the parts of a vault exert lateral thrust. When vaults are built underground, the ground gives all the resistance required. However, when the vault is built above ground, various replacements are employed to supply the needed resistance.
An example is the thicker walls used in the case of barrel or continuous vaults. Buttresses are used to supply resistance. Amongst the earliest known examples of any form of vaulting is to be found in the neolithic village of Khirokitia on Cyprus. Dating from ca. 6000 BCE, the circular buildings supported beehive shaped corbel domed vaults of unfired mud-bricks and represent the first evidence for settlements with an upper floor. Similar Beehive tombs, called tholoi, exist in Northern Iraq, their construction differs from that at Khirokitia in that most appear buried and make provision for a dromos entry. The inclusion of domes, represents a wider sense of the word vault; the distinction between the two is that a vault is an arch, extruded into the third dimension, whereas a dome is an arch revolved around its vertical axis. Pitched-brick vaults are named for their construction, the bricks are installed vertically and are leaning at an angle: This allows their construction to be completed without the use of centering.
Examples have been found in archaeological excavations in Mesopotamia dating to the 2nd and 3rd millennium BC which were set in gypsum mortar. A barrel vault is the simplest form of a vault and resembles a barrel or tunnel cut lengthwise in half; the effect is that of a structure composed of continuous pointed sections. The earliest known examples of barrel vaults were built by the Sumerians under the ziggurat at Nippur in Babylonia, built of fired bricks cemented with clay mortar; the earliest barrel vaults in ancient Egypt are thought to be those in the granaries built by the 19th dynasty Pharaoh Ramesses II, the ruins of which are behind the Ramesseum, at Thebes. The span was 12 feet and the lower part of the arch was built in horizontal courses, up to about one-third of the height, the rings above were inclined back at a slight angle, so that the bricks of each ring, laid flatwise, adhered till the ring was completed, no centering of any kind being required. A similar system of construction was employed for the vault over the great hall at Ctesiphon, where the material employed was fired bricks or tiles of great dimensions, cemented with mortar.
Assyrian palaces used pitched-brick vaults, made with sun-dried mudbricks, for gates, subterranean graves and drains. During the reign of king Sennacherib they were used to construct aqueducts, such as those at Jerwan. In the provincial city Dūr-Katlimmu they were used to created vaulted platforms; the tradition of their erection, would seem to have been handed down to their successors in Mesopotamia, viz. to the Sassanians, who in their palaces in Sarvestan and Firouzabad built domes of similar form to those shown in the Nimrud sculptures, the chief difference being that, constructed in rubble stone and cemented with mortar, they still exist, though abandoned on the Islamic invasion in the 7th century. In all the instances above quoted in Sumer and Egypt the bricks, whether burnt or sun-dried, were of the description to which the term "tile" would now be given; the earliest Egyptian examples of regular voussoirs in stone belong to the XXVIth Dynasty in the additions made to the temple of Medinet Habu, here it is probable that centering of some kind was provided, as the vaults are built in rings, so that the same centering could be shifted on after the completion of each ring.
The earliest example of shaped voussoirs, of about the same date, is found in the cloaca at Graviscae in Etruria, with a span of about 14 feet, the voussoirs of which are from 5 to 6 feet long. The cloaca maxima in Rome, built by Lucius Tarquinius Priscus to drain the marshy ground between the Palatine and the Capitoline Hills, was according to Commendatore Boni vaulted over in the 1st century B. C. the vault being over 800 feet long, 10 feet in span, with three concentric rings of voussoirs. The enormous Eyvan-e Khosro at Ctesiphon was built over 1,500 years ago during the Persian Sasanian period as a throne room; the arch is about