TRIUMPHAL ARCH, originally an arch built to commem orate a victory of a Roman general, but more commonly used, in a broader sense, for any monumental arch built for purely com memorative or even decorative purposes. The term is also used for the great arch between the nave and apse or the nave and transepts of an early Christian basilica. It is probable that temporary structures spanning a road or street were built by many peoples of antiquity to celebrate the homecoming of a victorious army, but it was the Romans who first made such arches permanent monumental structures, broadened their use for general memorial purposes, and even applied them to the monu mental gates of cities and towns. Obviously the building of such a structure as the developed Roman arch would occupy too much time to admit of its being used for the actual triumphal procession that it celebrated ; it was, therefore, originally, probably a recon struction in stone of an earlier, temporary archway.
Although no existing triumphal arches are earlier than the empire, it is known that there was, in the Forum, close to the regia, an arch commemorating the victory of Fabius Maximus Allobrogicus over the barbarians of Savoy in 121 B.C. Augustus built a triumphal arch on the Via Sacra, commemorating the victory of Crassus over the Parthians. From that time on there was hardly an emperor who did not build a triumphal arch somewhere in Rome. The greater number of these have per ished, but those of Titus (completed under Domitian c. A.D. 8o), of Septimius Severus (203-205) and that of Constantine (312), which incorporates much sculpture taken from the earlier arch of Trajan, still remain in good preservation. Many smaller monu mental arches also exist in Rome. Both emperors and private citizens built them in all the important centres of the empire. Monumental gateways of triumphal arch type exist in many places in Syria, like that probably of the time of Hadrian at Palmyra, and certain city gates were given the importance of a triumphal arch, especially that of Autun, France (probably 3rd century A.D.) and the Porta Nigra at Trier (4th centurY).
In the earlier arches, the arch is the most important element, usually with simple stretches of wall on either side. The orders appear only as minor decorative features, either under the arch impost, as at Saintes, or as flat pilasters, carrying a crowning entablature, and placed at the corners of the structure, as at S. Chamas. Only in the arches of Augustus, as at Susa and Aosta, do engaged columns appear, and even then, still as minor decora tive elements. It was in the arch of Titus, at Rome, that the later definite arrangement was worked out, in which the columns project boldly, on high pedestals, and carry an entablature that casts a strong shadow. Moreover, arch spandrils are sculptured, and the interior faces of the passage bear remarkable high relief panels, showing the seven branch candlestick and the other trophies of the capture of Jerusalem.
In the triple arch of Septimius Severus, the attic projects out over the end columns, the inscription runs through from end to end, so that the central columns are left without apparent work to do. In the arch of Constantine, on the other hand, the free-standing columns have become, like the pilasters of the early examples, purely decorative features, and each supports a colossal statue, so that despite the crudity of much of the workmanship, this arch gives the most satisfactory effect of any of the later arches in Rome. The Arch of Trajan at Timgad reveals another interesting attempt to relate free-standing col umns to the body of an arch, by connecting the two columns of each outer pair with a curved pediment, the attic over the central arch running up to a higher level. The triumphal arch of the early Christian basilica is chiefly remarkable as the posi tion for some of the richest and most beautiful of the wall mosaics that were the chief form of interior decoration. (See BASILICA; BYZANTINE AND ROMANESQUE ARCHITECTURE; MosAlc.) There is an interesting early Renaissance triumphal arch at Naples (1453-70), to commemorate the entrance of Alphonso I. into Aragon, designed by Pietro di Martino. The most interest ing Renaissance and modern triumphal arches are, however, of later date. The Porte Saint-Denis (1672-73), by Blonde' and the Porte Saint-Martin by Bullet, both in Paris, depart from the Roman scheme and substitute trophies and reliefs for the orders which the Romans used. Of the more Roman type, is the Arc de Triomphe du Carrousel, Paris (1805), by Percier and Fontaine, based on the arch of Septimius Severus. The Sieges Thor at Munich (1843-50), by Gaertner and Metzger, and the Marble Arch in London, designed in 1828 by John Nash for an entrance to Buckingham palace, and moved to its present posi tion in 1851, are both closely imitated from the Arch of Con stantine. The triple arch and screen at Hyde Park Corner, London (1828), by Decimus Burton, is a freer design, but still in the Roman manner. Another noteworthy modern arch is the Wash ington Arch, New York, by McKim, Mead and White, orig inally constructed in temporary materials in 1889 in celebration of the Iooth anniversary of Washington's inauguration, later reconstructed in marble and completed 1895. By far the largest of all triumphal arches and the most beautiful of modern examples is the Arc de Triomphe de l'Etoile at Paris (begun 1805 from designs by Chalgrin, but not completed till 1836). It is remark able for its architectural proportions and the great scale and almost stark grandeur of its sculpture, which emphasizes its great width of 147 ft. and height of i6o feet. Under the arch is the tomb of the "Unknown Warrior," over which burns, every night, the continuous "Flamme du Souvenir." (T. F. H.)