Discover Arch of Constantine

The Arch of Constantine is the largest of the three triumphal arches still standing in Rome, set between the Colosseum and the Palatine on the road that triumphs took between the Circus Maximus and the Arch of Titus.

It was put up in 315, commissioned by the Roman Senate, to celebrate Constantine's victory over Maxentius at the Milvian Bridge on 28 October 312.

And it is made of older monuments. It was built partly by reusing materials and architectural elements taken from imperial monuments of the ages of Trajan, Hadrian and Marcus Aurelius — which is why Turismo Roma calls it probably the first example of that systematic reuse of spoil which would go on in Rome all through the Middle Ages, and at the same time a precious synthesis of more than two centuries of official Roman art.

The detail that changes what you are looking at: all the faces of the emperors in the reliefs were remodelled to resemble Constantine, with the nimbus added to mark imperial majesty. Four reigns of sculpture, one face.

On its size the two authorities differ and we report both. Turismo Roma gives it as about 25 metres high. Wikipedia gives overall dimensions of 21 metres high, 25.9 metres wide and 7.4 metres deep, with a central bay 11.5 metres high and 6.5 wide and two lateral bays of 7.4 by 3.4 metres.

It costs nothing and takes twenty minutes. There is no interior, no ticket and no booking — it stands in the open behind railings, and the remains of the Meta Sudans lie in the ground beside it.

Three openings, four columns a side, and an attic heavy enough to carry eight statues. The central bay is the wide one, with a narrower bay either side; Wikipedia gives the central bay as 11.5 metres high and 6.5 wide, and the laterals as 7.4 by 3.4 metres each.

The construction is ordinary and the facing is not. The arch is built of brick-faced concrete covered in marble — a conventional Roman core wearing an exceptional skin.

The decoration is organised in registers, and each register is a different century. Above the lateral arches run friezes with Constantine's deeds in the campaign against Maxentius. Above those sit the Hadrianic roundels, with hunting and sacrifice scenes. In the attic are the great panels of the age of Marcus Aurelius, carrying episodes of the German war, flanking the long inscription.

The eight Dacians are the strongest vertical accent. They came from the Forum of Trajan and stand in the attic directly above the columns, so the column line continues upward as figures.

The column bases are part of the scheme, not a plinth. They are decorated with allegorical figures, which puts carving at eye level on a monument whose main interest is otherwise high above it.

The sizes reported for the whole differ by source. Turismo Roma: about 25 metres high. Wikipedia: 21 metres high, 25.9 wide, 7.4 deep. The figures are given as each authority gives them.

It was assembled rather than carved. The arch was built partly by reusing materials and architectural elements from older imperial monuments of the ages of Trajan, Hadrian and Marcus Aurelius — so much of the labour was in removal, selection and fitting rather than in sculpture.

That makes it a first, and the city says so. Turismo Roma calls it probably the first example of that systematic reuse of spoil material which in Rome would last throughout the Middle Ages.

The adaptation went as far as the faces. All the emperors in the reliefs were remodelled to resemble Constantine, with the nimbus added to denote imperial majesty — recutting portrait heads in situ rather than replacing the panels.

The core is standard imperial construction. Brick-faced concrete, then marble over it, which is how a structure of this size could be raised quickly.

And it was raised quickly: the victory was won on 28 October 312 and the arch was up by 315.

Later centuries kept working on it. Restorations ran from the end of the fifteenth century through the sixteenth, and in 1733 there were extensive integrations of the missing parts — so some of the stone is modern completion rather than Roman survival.

Can I walk under the arch? No. It is enclosed by railings and is seen from the surrounding pavement. There is no interior.

Does it cost anything? No. No ticket, no booking, no opening hours.

How tall is it? The two authorities differ. Turismo Roma says about 25 metres. Wikipedia gives 21 metres high, 25.9 wide and 7.4 deep. We report both.

Why do the emperors all look the same? Because they are the same. All the faces in the reused reliefs were remodelled to resemble Constantine, with a nimbus added to denote imperial majesty.

Which parts are not Constantine's? Most of the sculpture. The reliefs come from monuments of the ages of Trajan, Hadrian and Marcus Aurelius; the eight Dacians came from the Forum of Trajan. Only the narrow frieze above the lateral arches was made for this monument.

What is the stone circle in the grass beside it? The Meta Sudans, a Flavian-age monumental fountain. It was in use until the fifth century and its ruins were demolished in the 1930s to create via dei Trionfi.

When was it built, and why? Erected in 315 by the Roman Senate, for Constantine's victory over Maxentius at the Milvian Bridge on 28 October 312.

How long does it take? About twenty minutes, and it is thirty seconds from the Colosseum entrance.

Is it worth a special trip? Not on its own. It is worth the detour of a few metres from something you are already doing.