TRIUMPHAL ARCH. — In Christian architecture, the triumphal arch is the large arch that separates the central nave of the church from the presbytery, whether this includes the transept with the apse or the apse alone. In antiquity, it was often raised on two large columns, but in addition it was always distinguished by special decorations or reliefs, such as in the basilicas of Syria, or by mosaics, as in the great Roman basilicas.
Although the name of triumphal arch is only of medieval usage (and is found especially in the lives of the Popes of the 8th–9th centuries in the *Liber Pontificalis*, where it is also called *arcus maior*), we must trace its origin to the triumphal arches that Roman antiquity used to erect for victorious emperors. Just as the ornamental reliefs of these arches recount the glories of the heroes, so too on the triumphal arch of the Church it was customary to represent the triumph of Christ.
(Inst. Aliwali). In the triumphal arch of Galla Placidia in St Paul’s Outside the Walls in Rome, we find the majestic bust of Christ at the top, surrounded by the four apocalyptic beasts, while on the sides the twenty-four elders offer him their crowns. This apocalyptic triumph of Christ forms the preferred theme in the early Christian triumphal arch. Only occasionally, instead of the bust of Christ, we find the Lamb or the divine throne. Alongside this representation, we often also find Christ seated upon the globe of the universe between apostles or saints, as for example at Porto, in St Lawrence Outside the Walls, and in St Agatha of the Goths in Rome.
In the Middle Ages, the triumph of Christ was represented on the triumphal arch in a manner certainly no less profound and expressive, namely by the so-called triumphal cross. At the beginning of the curvature of the arch, the nave was crossed high above by a large beam, upon which stood a monumental cross, often accompanied by the Virgin and St John—a magnificent application of the triumphal hymn of Good Friday, *Vexilla regis prodeunt...* by Venantius Fortunatus. Unfortunately, in later times this beautiful expression of the triumph of Christ was often removed from churches, and with the new forms of a new architecture the ancient triumphal arch also disappeared.