Triumphal arch

A triumphal arch is a free-standing monumental structure in the shape of an archway with one or more arched passageways, often designed to span a road, and usually standing alone, unconnected to other buildings. In its simplest form, a triumphal arch consists of two massive piers connected by an arch, typically crowned with a flat entablature or attic on which a statue might be mounted or which bears commemorative inscriptions. The main structure is often decorated with carvings, sculpted reliefs, and dedications. More elaborate triumphal arches may have multiple archways, or in a tetrapylon, passages leading in four directions.

Triumphal arches are one of the most influential and distinctive types of ancient Roman architecture. Effectively invented by the Romans, and using their skill in making arches and vaults, the Roman triumphal arch was used to commemorate victorious generals or significant public events such as the founding of new colonies, the construction of a road or bridge, the death of a member of the imperial family or the accession of a new emperor.

Archaeologists like to distinguish between a true "triumphal arch", built to celebrate an actual Roman triumph, a grand procession declared by the Roman Senate following military victory; a "memorial arch" or "honourary arch", essentially built by emperors to celebrate themselves; and arches, typically in city walls, that are merely grand gateways. Often actual Roman triumphal arches were initially in wood and other rather temporary materials, only later replaced by one in stone; the majority of ancient survivals are actually from the other two groups.

The survival of great Roman triumphal arches such as the Arch of Titus or the Arch of Constantine has inspired many post-Roman states and rulers, up to the present day, to erect their own triumphal arches in emulation of the Romans. Triumphal arches in the Roman style have been built in many cities around the world, including the Arc de Triomphe in Paris, the Narva Triumphal Arch in Saint Petersburg, or Marble Arch and the Wellington Arch in London. After about 1820 arches are often memorial gates and arches built as a form of war memorial, or city gates such as the Brandenburg Gate in Berlin, the Washington Square Arch in New York City, or the India Gate in New Delhi, which although patterned after triumphal arches, were built to memorialise war casualties, to commemorate a civil event (the country's independence, for example), or to provide a monumental entrance to a city, as opposed to celebrating a military success or general.

In architecture, "triumphal arch" is also the name given to the arch above the entrance to the chancel of a medieval church where a rood can be placed. and more generally a combination of "one large and two small doorways", such as Leon Battista Alberti's façades for the Tempio Malatestiano and San Andrea, Mantua.

Roman aqueducts, bridges, amphitheaters and domes employed arch principles and technology. The Romans probably borrowed the techniques of arch construction from their Etruscan neighbours. The Etruscans used elaborately decorated single bay arches as gates or portals to their cities; examples of Etruscan arches survive at Perugia and Volterra.

The two key elements of the Roman triumphal arch – a round-topped arch and a square entablature – had long been in use as separate architectural elements in ancient Greece, but the Greeks preferred the use of entablatures in their temples, and almost entirely confined their use of the arch to structures under external pressure, such as tombs and sewers. The Roman triumphal arch combined a round arch and a square entablature in a single free-standing structure. What were originally supporting 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 through the use of statuary and symbolic, narrative and decorative elements.

The largest arches often had three archways, the central one significantly larger. The minority type of arch with passageways in both directions, often placed at crossroads, is called a tetrapylon (or arcus quadrifrons in Latin), as it has four piers. Roman examples are usually roughly cubical, like the Arch of Septimius Severus in Leptis Magna, Libya, but modern examples, like the Arc de Triomphe, tend to be oblong, with clear main faces and smaller side faces. Examples with three arches on the long face as well as arches at the ends, so with eight piers, are called octopylons. The Arc de Triomphe du Carrousel in Paris is an example.