Located on the Roman street along which triumphs passed, in the stretch between the Circus Maximus and the Arch of Titus, the Arch of Constantine is the largest honorary arch that has come down to us and is a synthesis of the ideological propaganda of Constantine’s age. The arch celebrates the triumph of the emperor Constantine over Maxentius, which took place on October 28, A.D. 312, following the victorius battle at the Milvian bridge. As we learn from the inscription over the main arch, the monument was solemnly dedicated to the emperor by the Senate in memory of that triumph and on the occasion of the decennalia of the Empire, at the beginning of the tenth year of his reign on July, 25, 315.
In the middle of the twelfth century the monument was incorporated into the Frangipane fortress. It was restored and studied at the end of the fifteenth century and throughout the sixteenth, but the most significant activity in this respect dates from 1733, when many missing parts were replaced.
The three arches are decorated by marble slabs with reliefs. It was conceived and executed during Constantine’ reign as an integrated whole, utilizing mainly materials plundered from other imperial monuments. On the main faces and short side of the arch there are reliefs from the ages of Trajan, Hadrian and Marcus Aurelius, while the lower part presents ones from the reign of Constantine. They provide a valuable sample of the figurative language of the imperial propaganda: a concise overview of more than two centuries of history of official Roman art. The four panel from Trajan’s time originally made up a continuous frieze and must have decorated the Forum of Trajan as part of the facing of the attic of the Basilica Ulpia. It has recently been suggested that the rondels from Hadrian’s reign originally decorated the entrance arch of a sanctuary dedicated to the heroic cult of Antinoo, the young man loved by the emperor, who in effect appears in varius hunting and sacrificial scenes.
The reliefs of Marcus Aurelius – to which three other panels of similar size and subject are now on display in the Palazzo dei Conservatori – come form the Arcus Panis Aurei on the slopes of the Capitoline hill, an honorary arch celebrating the emperors’ triumph over the Germanic tribes. The faces of all the emperors portrayed in the reliefs were remodelled to resemble Constantine, with a nimbus connoting imperial majesty. The face of Licinius, the emperor of the East, appears in the rondels with sacrificial scenes. In the panels from the reign of Marcus Aurelius, the head is Trajan’s and was inserted during the eighteenth-century restoration.
The many images crowding the sides of the arch are actually connected by a precise leitmotiv: the celebration of Constantine’s project of restoring the Empire. He wanted to be acknowledged and celebrated as the legitimate victor over his tyrannical rival, Maxentius, and the new arbiter of Rome’s future, and to this end chose a traditional monument that was deeply rooted in imperial history: the arch. He designated it to narrate his victories and crown his role in power, but decided to decorate it with older images taken from the memory of other buildings. Diocletian had done the same thing before him, composing the so-called Arcus Novus on Via Lata with plundered decoration.
In the constant dialogue between past and present, the memory of the great figures of the Empire suggested a temporal continuity between Constantine and the optimi princeps of the golden age. This consideration contributes to the understanding of the organization of the images on the two longer sides: on the south side scenes of war and on the north one scenes of peace and public life, which ideally accompanied the triumphal procession from outside the city (South) and inside it (North). In this absolute and almost abstract vision of war and peace, his address to the troups, clemency towards the defeated, pietas towards the gods and generosity towards the people summed up the sovereign’s virtues and celebrated his moral stature in emblematic and symbolic scenes.