Roman Architecture covers the period from the establishment of the Roman Republic in 509 BC to about the 4th century AD, after which it becomes reclassified as Late Antique or Byzantine architecture. Almost no substantial examples survive from before about 100 BC, and most of the major survivals are from the later empire, after about 100 AD. Roman architectural style continued to influence building in the former empire for many centuries, and the style used in Western Europe beginning about 1000 is called Romanesque architecture to reflect this dependence on basic Roman forms.

The Romans only began to achieve significant originality in architecture around the beginning of the Imperial period, after they had combined aspects of their original Etruscan architecture with others taken from Greece, including most elements of the style we now call classical architecture. They moved from trabeated construction mostly based on columns and lintels to one based on massive walls, punctuated by arches, and later domes, both of which greatly developed under the Romans. The classical orders now became largely decorative rather than structural, except in colonnades. Stylistic developments included the Tuscan and Composite orders; the first being a shortened, simplified variant on the Doric order and the Composite being a tall order with the floral decoration of the Corinthian and the scrolls of the Ionic. The period from roughly 40 BC to about 230 AD saw most of the greatest achievements, before the Crisis of the Third Century and later troubles reduced the wealth and organizing power of the central government.

Factors such as wealth and high population densities in cities forced the ancient Romans to discover new architectural solutions of their own. The use of vaults and arches, together with a sound knowledge of building materials, enabled them to achieve unprecedented successes in the construction of imposing infrastructure for public use. Examples include the aqueducts of Rome, the Baths of Diocletian and the Baths of Caracalla, the basilicas and Colosseum. These were reproduced at a smaller scale in most important towns and cities in the Empire. Some surviving structures are almost complete, such as the town walls of Lugo in Hispania Tarraconensis, now northern Spain. The administrative structure and wealth of the empire made possible very large projects even in locations remote from the main centres, as did the use of slave labour, both skilled and unskilled.

Especially under the empire, architecture often served a political function, demonstrating the power of the Roman state in general, and of specific individuals responsible for building. Roman architecture perhaps reached its peak in the reign of Hadrian, whose many achievements include rebuilding the Pantheon in its current form and leaving his mark on the landscape of northern Britain with Hadrian’s Wall.

Decorative structures

Monoliths
In architecture, a monolith is a structure which has been excavated as a unit from a surrounding matrix or outcropping of rock. Monoliths are found in all types of Roman buildings. They were either: quarried without being moved; or quarried and moved; or quarried, moved and lifted clear off the ground into their position (e.g. architraves); or quarried, moved and erected in an upright position (e.g. columns).

Transporting was done by land or water (or a combination of both), in the later case often by special-built ships such as obelisk carriers. For lifting operations, ancient cranes were employed since ca. 515 BC, such as in the construction of Trajan’s Column.

Obelisks
An obelisk is a tall, four-sided, narrow tapering monument which ends in a pyramid-like shape at the top. These were originally called “tekhenu” by the builders, the ancient Egyptians. The Greeks who saw them used the Greek ‘obeliskos’ to describe them, and this word passed into Latin and then English. The Romans commissioned obelisks in an ancient Egyptian style. Examples include:

Arles, France – the Arles Obelisk, in Place de la République, a 4th-century obelisk of Roman origin
Benevento, Italy – three Roman obelisks
Munich – obelisk of Titus Sextius Africanus, Staatliches Museum Ägyptischer Kunst, Kunstareal, 1st century AD, 5.80 m
Rome – there are five ancient Roman obelisks in Rome.

Roman gardens
Roman gardens were influenced by Egyptian, Persian, and Greek gardening techniques. In Ancient Latium, a garden was part of every farm. According to Cato the Elder, every garden should be close to the house and should have flower beds and ornamental trees. Horace wrote that during his time flower gardens became a national indulgence.

Gardens were not reserved for the extremely wealthy. Excavations in Pompeii show that gardens attaching to residences were scaled down to meet the space constraints of the home of the average Roman. Modified versions of Roman garden designs were adopted in Roman settlements in Africa, Gaul, and Britannia. As town houses were replaced by tall insula (apartment buildings), these urban gardens were replaced by window boxes or roof gardens.

Triumphal arch
A triumphal arch is a monumental structure in the shape of an archway with one or more arched passageways, often designed to span a road. The origins of the Roman triumphal arch are unclear. There were precursors to the triumphal arch within the Roman world; in Italy, the Etruscans used elaborately decorated single bay arches as gates or portals to their cities. Surviving examples of Etruscan arches can still be seen at Perugia and Volterra. The two key elements of the triumphal arch – a round-topped arch and a square entablature – had long been in use as separate architectural elements in ancient Greece.

The innovation of the Romans was to use these elements in a single free-standing structure. The columns became purely decorative elements on the outer face of arch, while the entablature, liberated from its role as a building support, became the frame for the civic and religious messages that the arch builders wished to convey. Little is known about how the Romans viewed triumphal arches. Pliny the Elder, writing in the first century AD, was the only ancient author to discuss them. He wrote that they were intended to “elevate above the ordinary world” an image of an honoured person usually depicted in the form of a statue with a quadriga.

The first recorded Roman triumphal arches were set up in the time of the Roman Republic. Generals who were granted a triumph were termed triumphators and would erect fornices or honorific arches bearing statues to commemorate their victories. Roman triumphal practices changed significantly at the start of the imperial period when the first Roman Emperor Augustus decreed that only emperors would be granted triumphs. The triumphal arch changed from being a personal monument to being an essentially propagandistic one, serving to announce and promote the presence of the ruler and the laws of the state. Arches were not necessarily built as entrances, but – unlike many modern triumphal arches – they were often erected across roads and were intended to be passed through, not round.

Most Roman triumphal arches were built during the imperial period. By the fourth century AD there were 36 such arches in Rome, of which three have survived – the Arch of Titus (AD 81), the Arch of Septimius Severus (203-205) and the Arch of Constantine (312). Numerous arches were built elsewhere in the Roman Empire. The single arch was the most common, but many triple arches were also built, of which the Triumphal Arch of Orange (circa AD 21) is the earliest surviving example. From the 2nd century AD, many examples of the arcus quadrifrons – a square triumphal arch erected over a crossroads, with arched openings on all four sides – were built, especially in North Africa. Arch-building in Rome and Italy diminished after the time of Trajan (AD 98-117) but remained widespread in the provinces during the 2nd and 3rd centuries AD; they were often erected to commemorate imperial visits.

The ornamentation of an arch was intended to serve as a constant visual reminder of the triumph and triumphator. The façade was ornamented with marble columns, and the piers and attics with decorative cornices. Sculpted panels depicted victories and achievements, the deeds of the triumphator, the captured weapons of the enemy or the triumphal procession itself. The spandrels usually depicted flying Victories, while the attic was often inscribed with a dedicatory inscription naming and praising the triumphator. The piers and internal passageways were also decorated with reliefs and free-standing sculptures. The vault was ornamented with coffers. Some triumphal arches were surmounted by a statue or a currus triumphalis, a group of statues depicting the emperor or general in a quadriga.

Inscriptions on Roman triumphal arches were works of art in themselves, with very finely cut, sometimes gilded letters. The form of each letter and the spacing between them was carefully designed for maximum clarity and simplicity, without any decorative flourishes, emphasizing the Roman taste for restraint and order. This conception of what later became the art of typography remains of fundamental importance down to the present day.

Victory columns

Infrastructure

Roads
Roman roads were vital to the maintenance and development of the Roman state, and were built from about 500 BC through the expansion and consolidation of the Roman Republic and the Roman Empire. They provided efficient means for the overland movement of armies, officials and civilians, and the inland carriage of official communications and trade goods. At the peak of Rome’s development, no fewer than 29 great military highways radiated from the capital, and the Late Empire’s 113 provinces were interconnected by 372 great road links. Roman road builders aimed at a regulation width (see Laws and standards above), but actual widths have been measured at between 3.6 ft (1.1 m) and more than 23 ft (7.0 m). Today, the concrete has worn from the spaces around the stones, giving the impression of a very bumpy road, but the original practice was to produce a surface that was no doubt much closer to being flat.

Aqueduct
The Romans constructed numerous aqueducts in order to bring water from distant sources into their cities and towns, supplying public baths, latrines, fountains and private households. Waste water was removed by complex sewage systems and released into nearby bodies of water, keeping the towns clean and free from effluent. Aqueducts also provided water for mining operations, milling, farms and gardens.

Aqueducts moved water through gravity alone, being constructed along a slight downward gradient within conduits of stone, brick or concrete. Most were buried beneath the ground, and followed its contours; obstructing peaks were circumvented or, less often, tunnelled through. Where valleys or lowlands intervened, the conduit was carried on bridgework, or its contents fed into high-pressure lead, ceramic or stone pipes and siphoned across. Most aqueduct systems included sedimentation tanks, sluices and distribution tanks to regulate the supply at need.

Rome’s first aqueduct supplied a water-fountain sited at the city’s cattle market. By the third century AD, the city had eleven aqueducts, sustaining a population of over a million in a water-extravagant economy; most of the water supplied the city’s many public baths. Cities and municipalities throughout the Roman Empire emulated this model, and funded aqueducts as objects of public interest and civic pride, “an expensive yet necessary luxury to which all could, and did, aspire.”

Most Roman aqueducts proved reliable, and durable; some were maintained into the early modern era, and a few are still partly in use. Methods of aqueduct surveying and construction are noted by Vitruvius in his work De Architectura (1st century BC). The general Frontinus gives more detail in his official report on the problems, uses and abuses of Imperial Rome’s public water supply. Notable examples of aqueduct architecture include the supporting piers of the Aqueduct of Segovia, and the aqueduct-fed cisterns of Constantinople.

Bridges
Roman bridges, built by ancient Romans, were the first large and lasting bridges built. Roman bridges were built with stone and had the arch as the basic structure (see arch bridge). Most utilized concrete as well, which the Romans were the first to use for bridges.

Roman arch bridges were usually semicircular, although a few were segmental (such as Alconétar Bridge). A segmental arch is an arch that is less than a semicircle. The advantages of the segmental arch bridge were that it allowed great amounts of flood water to pass under it, which would prevent the bridge from being swept away during floods and the bridge itself could be more lightweight. Generally, Roman bridges featured wedge-shaped primary arch stones (voussoirs) of the same in size and shape. The Romans built both single spans and lengthy multiple arch aqueducts, such as the Pont du Gard and Segovia Aqueduct. Their bridges featured from an early time onwards flood openings in the piers, e.g. in the Pons Fabricius in Rome (62 BC), one of the world’s oldest major bridges still standing. Roman engineers were the first and until the industrial revolution the only ones to construct bridges with concrete, which they called Opus caementicium. The outside was usually covered with brick or ashlar, as in the Alcántara bridge.

The Romans also introduced segmental arch bridges into bridge construction. The 330 m long Limyra Bridge in southwestern Turkey features 26 segmental arches with an average span-to-rise ratio of 5.3:1, giving the bridge an unusually flat profile unsurpassed for more than a millennium. Trajan’s bridge over the Danube featured open-spandrel segmental arches made of wood (standing on 40 m high concrete piers). This was to be the longest arch bridge for a thousand years both in terms of overall and individual span length, while the longest extant Roman bridge is the 790 m long Puente Romano at Mérida.

Canals
Roman canals were typically multi-purpose structures, intended for irrigation, drainage, land reclamation, flood control and navigation where feasible. Some navigational canals were recorded by ancient geographers and are still traceable by modern archaeology. Channels which served the needs of urban water supply are covered at the List of aqueducts in the Roman Empire.

Cisterns
Freshwater reservoirs were commonly set up at the termini of aqueducts and their branch lines, supplying urban households, agricultural estates, imperial palaces, thermae or naval bases of the Roman navy.

Dams
Roman dam construction began in earnest in the early imperial period. For the most part, it concentrated on the semi-arid fringe of the empire, namely the provinces of North Africa, the Near East, and Hispania. The relative abundance of Spanish dams below is due partly to more intensive field work there; for Italy only the Subiaco Dams, created by emperor Nero (54–68 AD) for recreational purposes, are attested. These dams are noteworthy, though, for their extraordinary height, which remained unsurpassed anywhere in the world until the Late Middle Ages.

The most frequent dam types were earth- or rock-filled embankment dams and masonry gravity dams. These served a wide array of purposes, such as irrigation, flood control, river diversion, soil-retention, or a combination of these functions. The impermeability of Roman dams was increased by the introduction of waterproof hydraulic mortar and especially opus caementicium in the Concrete Revolution. These materials also allowed for bigger structures to be built, like the Lake Homs Dam, possibly the largest water barrier today, and the sturdy Harbaqa Dam, both of which consist of a concrete core.

Roman builders were the first to realize the stabilizing effect of arches and buttresses, which they integrated into their dam designs. Previously unknown dam types introduced by the Romans include arch-gravity dams, arch dams,; buttress dams, and multiple-arch buttress dams.

Defensive walls
The Romans generally fortified cities, rather than fortresses, but there are some fortified camps, such as the Saxon Shore forts like Porchester Castle in England. City walls were already significant in Etruscan architecture, and in the struggle for control of Italy under the early Republic many more were built, using different techniques. These included tightly-fitting massive irregular polygonal blocks, shaped to fit exactly in a way reminiscent of later Inca work. The Romans called a simple rampart wall an agger; at this date great height was not necessary. The Servian Wall around Rome was an ambitious project of the early 4th century BC. The wall was up to 10 metres (32.8 ft) in height in places, 3.6 metres (12 ft) wide at its base, 11 km (7 mi) long, and is believed to have had 16 main gates, though many of these are mentioned only from writings, with no other known remains. Some of it had a fossa or ditch in front, and an agger behind, and it was enough to deter Hannibal. Later the Aurelian Wall replaced it, enclosing an expanded city, and using more sophisticated designs, with small forts at intervals.

The Romans walled major cities and towns in areas they saw as vulnerable, and parts of many walls remain incorporated in later defences, as at Córdoba (2nd century BC), Chester (earth and wood in the 70s AD, stone from c. 100), and York (from 70s AD). Strategic walls across open country were far rarer, and Hadrian’s Wall (from 122) and the Antonine Wall (from 142, abandoned only 8 years after completion) are the most significant examples, both on the Pictish frontier.

Architectural features

Mosaics
On his return from campaigns in Greece, the general Sulla brought back what is probably the most well-known element of the early imperial period, the mosaic, a decoration made of colourful chips of stone inserted into cement. This tiling method took the empire by storm in the late first century and the second century and in the Roman home joined the well known mural in decorating floors, walls, and grottoes with geometric and pictorial designs.

There were two main techniques in Greco-Roman mosaic: opus vermiculatum used tiny tesserae, typically cubes of 4 millimeters or less, and was produced in workshops in relatively small panels which were transported to the site glued to some temporary support. The tiny tesserae allowed very fine detail, and an approach to the illusionism of painting. Often small panels called emblemata were inserted into walls or as the highlights of larger floor-mosaics in coarser work. The normal technique, however, was opus tessellatum, using larger tesserae, which were laid on site. There was a distinct native Italian style using black on a white background, which was no doubt cheaper than fully coloured work.

A specific genre of Roman mosaic obtained the name asaroton (Greek “unswept floor”). It represented an optical illusion of the leftovers from a feast on the floor of reach houses.

Hypocaust
A hypocaust was an ancient Roman system of underfloor heating, used to heat houses with hot air. The Roman architect Vitruvius, writing about the end of the 1st century B.C., attributes their invention to Sergius Orata. Many remains of Roman hypocausts have survived throughout Europe, western Asia, and northern Africa. The hypocaust was an invention which improved the hygiene and living conditions of citizens, and was a forerunner of modern central heating.

Hypocausts were used for heating hot baths (thermae), houses and other buildings, whether public or private. The floor was raised above the ground by pillars, called pilae stacks, with a layer of tiles, then a layer of concrete, then another of tiles on top; and spaces were left inside the walls so that hot air and smoke from the furnace would pass through these enclosed areas and out of flues in the roof, thereby heating but not polluting the interior of the room.

Roman roofs
In Sicily truss roofs presumably appeared as early as 550 BC.Their potential was fully realized in the Roman period, which saw trussed roofs over 30 wide spanning the rectangular spaces of monumental public buildings such as temples, basilicas, and later churches. Such spans were three times as wide as the widest prop-and-lintel roofs and only surpassed by the largest Roman domes.

The largest truss roof by span of ancient Rome covered the Aula Regia (throne room) built for emperor Domitian (81–96 AD) on the Palatine Hill, Rome. The timber truss roof had a width of 31.67 m, slightly surpassing the postulated limit of 30 m for Roman roof constructions. Tie-beam trusses allowed for much larger spans than the older prop-and-lintel system and even concrete vaulting. Nine out of the ten largest rectangular spaces in Roman architecture were bridged this way, the only exception being the groin vaulted Basilica of Maxentius.

Spiral stairs
The spiral stair is a type of stairway which, due to its complex helical structure, was introduced relatively late into architecture. Although the oldest example dates back to the 5th century BC, it was only in the wake of the influential design of Trajan’s Column that this space-saving new type permanently caught hold in Roman architecture.

Apart from the triumphal columns in the imperial cities of Rome and Constantinople, other types of buildings such as temples, thermae, basilicas and tombs were also fitted with spiral stairways. Their notable absence in the towers of the Aurelian Wall indicates that although used in medieval castles, they did not yet figure prominently in Roman military engineering. By late antiquity, separate stair towers were constructed adjacent to the main buildings, as in the Basilica of San Vitale.

The construction of spiral stairs passed on both to Christian and Islamic architecture.

Source From Wikipedia