Arco di Costantino (Arch of Constantine), Rome

On October 28, 312 AD, Roman emperor Constantine had an epic battle with his rival, co-emperor Maxentius. It went down in history as the Battle of the Milvian Bridge. Victorious Constantine became the sole ruler of the Roman Empire, thus ending the system of Tetrarchy. He is generally regarded as the last great emperor of Rome.

The Arch of Constantine, Rome’s largest triumphal arch, was dedicated in 315 AD to commemorate Constantine’s victory. Located between the Colosseum and Palatine Hill, it spans the Road of Triumph, marking the route of Roman military parades. The arch stands 21 meters high, featuring three bays and incorporating elements from earlier monuments, including reliefs and statues from the reigns of Trajan, Hadrian, and Marcus Aurelius, reworked to celebrate Constantine.

Scholars have debated the arch's origins, suggesting it may predate Constantine and even have ties to Hadrian’s or Maxentius’s reigns. The arch exemplifies Late Antique artistic styles, with a blend of reused classical Greek-inspired elements and newly-created simpler, symbolic works. Reliefs from earlier monuments display classical proportions and dynamic movement, while the 4th-century additions feature rigid and geometric forms, reflecting changes in artistic priorities or economic constraints at that time. This stylistic contrast highlights the transition from Rome’s classical tradition to the evolving aesthetics of Late Antiquity.

Decorative elements on the arch include reliefs of Dacians from Trajan’s reign, panels depicting Marcus Aurelius’s military campaigns, and roundels from Hadrian’s era reworked to depict Constantine. A Constantinian frieze narrates his campaign against Maxentius, while inscriptions celebrate him as a pious and victorious leader.

One such inscription credits Constantine with saving the Roman people by divine inspiration. It refers to his vision before the Battle of Milvian Bridge in 312 AD, where he claimed to have seen a cross in the sky and heard the words: "In this sign, you will conquer." This event is often linked to Constantine's promotion of Christianity within the Roman Empire. The arch also balances pagan and Christian themes, symbolizing Constantine’s shifting religious stance during this period.

The Arch of Constantine's global influence as a monument includes the likes of the Arch of Triumph in Paris, the Marble Arch in London, Washington Union Station in Washington DC, and the American Museum of Natural History in New York City.