Editing Ancient Roman architecture (section)

== Materials ==

===Stone===
[[File:3223 - Roma - Santa Maria degli Angeli - Interno - Foto Giovanni Dall'Orto 17-June-2007.jpg|thumb|Frigidarium of [[Baths of Diocletian]], today [[Santa Maria degli Angeli e dei Martiri|Santa Maria degli Angeli]]]]

[[Marble]] is not found especially close to Rome, and was only rarely used there before [[Augustus]], who famously boasted that he had found Rome made of brick and left it made of marble, though this was mainly as a facing for brick or concrete. The [[Temple of Hercules Victor]] of the late 2nd century BC is the earliest surviving exception in Rome. From Augustus' reign the quarries at [[Carrara]] were extensively developed for the capital, and other sources around the empire exploited,<ref>Henig, p. 28</ref> especially the prestigious Greek marbles like [[Parian marble|Parian]]. [[Travertine]] [[limestone]] was found much closer, around [[Tivoli, Lazio|Tivoli]], and was used from the end of the Republic; the [[Colosseum]] is mainly built of this stone, which has good load-bearing capacity, with a brick core.<ref>Henig, p. 32</ref> Other more or less local stones were used around the Empire.<ref>Favro, (ii) Materials and construction techniques</ref>

The Romans were fond of luxury imported coloured marbles with fancy veining, and the interiors of the most important buildings were often faced with slabs of these, which have usually now been removed even where the building survives. Imports from Greece for this purpose began in the 2nd century BC.<ref>Henig, p. 22; Favro, (ii) Materials and construction techniques, which lists major quarries</ref>

=== Roman brick ===
{{Main|Roman brick}}
[[File:Gariannonum Burgh Castle south wall well preserved close up.jpg|thumb|Close-up view of the wall of the Roman [[Saxon Shore|shore fort]] at [[Burgh Castle (Roman fortification)|Burgh Castle]], Norfolk, showing alternating courses of [[flint]] and brickwork]]
[[File:Храм_Свети_Великомъченик_Георги_Победоносец.jpg|thumb|The [[Church of St. George, Sofia|St. George Rotunda]] (4th century) and remains of [[Serdica]], [[Sofia]], [[Bulgaria]]]]
The Romans made [[Roman brick|fired clay bricks]] from about the beginning of the Empire, replacing earlier sun-dried [[mudbrick]]. Roman brick was almost invariably of a lesser height than modern brick, but was made in a variety of different shapes and sizes.{{sfn|Juracek|1996|p=310}} Shapes included square, rectangular, triangular and round, and the largest bricks found have measured over three feet in length.{{sfn|Peet|1911|pp=35–36}} Ancient Roman bricks had a general size of 1½ [[Foot (unit of length)#Historical origin|Roman feet]] by 1 Roman foot, but common variations up to 15 inches existed. Other brick sizes in ancient Rome included 24" x 12" x 4", and 15" x 8" x 10". Ancient Roman bricks found in France measured 8" x 8" x 3". The [[Aula Palatina|Constantine Basilica]] in [[Trier]] is constructed from Roman bricks 15" square by 1½" thick.{{sfn|Walters|Birch|1905|p=330–40}} There is often little obvious difference (particularly when only fragments survive) between Roman bricks used for walls on the one hand, and [[Imbrex and tegula|tiles]] used for roofing or flooring on the other, so archaeologists sometimes prefer to employ the generic term [[ceramic building material]] (CBM).

The Romans perfected brick-making during the first century of their empire and used it ubiquitously, in public and private construction alike. They took their brickmaking skills everywhere they went, introducing the craft to the local populations.{{sfn|Walters|Birch|1905|p=330–40}} The [[Roman legion]]s, which operated their own [[kiln]]s, introduced bricks to many parts of the Empire; bricks are often stamped with the mark of the legion that supervised their production. The use of bricks in southern and western Germany, for example, can be traced to traditions already described by the Roman architect [[Vitruvius]]. In the [[British Isles]], the introduction of Roman brick by the ancient Romans was followed by a 600–700 year gap in major brick production.

=== Roman concrete ===
{{Main|Roman concrete}}
[[File:OpusCaementiciumViaAppiaAntica.jpg|thumb|Example of ''opus caementicium'' on a tomb on the ancient [[Appian Way]] in Rome. The original covering has been removed.]]

Concrete quickly supplanted brick as the primary building material,{{citation needed|date=March 2016}} and more daring buildings soon followed, with great [[pillar]]s supporting broad [[arch]]es and [[domes]] rather than dense lines of columns suspending flat [[architrave]]s. The freedom of concrete also inspired the [[colonnade]] screen, a row of purely decorative columns in front of a load-bearing wall. In smaller-scale architecture, concrete's strength freed the [[floor plan]] from rectangular cells to a more free-flowing environment.{{Citation needed|date=July 2014}} Most of these developments are described by [[Vitruvius]], writing in the first century BC in his work ''[[De architectura]]''.

Although concrete had been used on a minor scale in Mesopotamia, Roman architects perfected [[Roman concrete]] and used it in buildings where it could stand on its own and support a great deal of weight. The first use of concrete by the Romans was in the town of [[Cosa]] sometime after 273 BC. Ancient Roman concrete was a mixture of [[lime mortar]], [[Aggregate (composite)|aggregate]], [[pozzolana]], water, and [[stones]], and was stronger than previously used concretes. The ancient builders placed these ingredients in wooden frames where they hardened and bonded to a facing of stones or (more frequently) bricks. The aggregates used were often much larger than in modern concrete, amounting to rubble.

When the framework was removed, the new wall was very strong, with a rough surface of bricks or stones. This surface could be smoothed and faced with an attractive [[stucco]] or thin panels of marble or other coloured stones called a "revetment". Concrete construction proved to be more flexible and less costly than building solid stone buildings. The materials were readily available and not difficult to transport. The wooden frames could be used more than once, allowing builders to work quickly and efficiently. Concrete is arguably the Roman contribution most relevant to modern architecture.