Basilica of Maxentius

Stand still for a moment and look up. Above you, three enormous arches open into the Roman sky. Their undersides are cut into deep square hollows, like the inside of a giant honeycomb. The brick is warm and rough, the colour of baked earth. Swifts cut through the air in quick dark lines, and below them the footsteps of the Forum crunch on old gravel. What you see is only a fragment of a building. Even so, it is one of the largest fragments of ancient Rome still standing.

This is the Basilica of Maxentius, sometimes called the Basilica of Constantine. Both names are correct, and the story of why is the story of the building itself. Work began in the early fourth century under the emperor Maxentius. He ruled Rome during a time of rival emperors and civil war. He wanted to show that Rome, the old capital, still mattered. So he set out to build the grandest civic hall the Forum had ever seen.

First, a word about that word, basilica. Today it suggests a church. In ancient Rome, it meant something quite different. A basilica was a large public hall — a place for law courts, business meetings, and official ceremonies. Think of it as a mix of courthouse, town hall, and covered market. Christian churches borrowed the shape later. So when you stand here, picture lawyers arguing and officials at work, not priests at an altar.

Maxentius never saw his hall finished. In 312, he met his rival Constantine in battle at the Milvian Bridge, just north of the city. Maxentius lost, and he drowned in the Tiber River. Constantine entered Rome as the victor. He took over the unfinished basilica and completed it in his own name. He also changed its plan. He added a new entrance from the Sacred Way, the main street of the Forum, and a second apse, a rounded end wall, facing it.

Now look again at the three arches in front of you. These are the remains of only one side of the building — the northern aisle. Originally, a matching row of three stood on the opposite side. Between them rose a central hall, much taller still, roofed with huge vaults. If you imagine the arches you see doubled, and then a higher space joining them in the middle, you begin to sense the full scale. The building was the largest in the Forum.

Here is something many visitors miss. Most earlier Roman basilicas had flat timber roofs held up by rows of columns. This one did not. Its builders used Roman concrete, poured in great curves and faced with brick. The concrete carried the weight of the vaults. That is why these arches have survived when so many timber-roofed halls are gone. The engineering is closer to the great public baths of Rome than to a traditional basilica.

Look closely at those square hollows in the vaults. They are called coffers. They made the ceiling lighter, so less weight pressed down on the walls. They also gave the surface a rhythm of light and shadow. Originally, the interior was finished with fine stone, stucco, and colour. What you see now is the structural skeleton. The bare brick shows how the building was actually made.

The basilica also held a giant. In the western apse sat a colossal seated statue of Constantine. Its head, hands, and feet were carved from white marble. The body was probably built from a frame covered with bronze or other material. Fragments of this statue were found here at the end of the fifteenth century. Today the huge head, a hand, and a foot sit in a courtyard of the Capitoline Museums, a short walk away. The head alone is taller than a person. If you visit the museums later, you will meet the man who finished this hall.

So what brought most of this building down? Over the centuries, Rome changed, and the hall lost its purpose. Materials were removed and reused. Then, in the ninth century, a major earthquake struck the city. The southern side and the great central vaults collapsed. Only this northern row held. The rest became rubble, and over time the Forum around it filled with earth.

One piece of the basilica still stands somewhere else in Rome — and still upright. The central hall once had tall marble columns. One of them survived. In the early seventeenth century, Pope Paul V had it moved across the city. It now stands in the square in front of the Basilica of Santa Maria Maggiore, with a statue of the Virgin Mary on top. So a column from this civic hall now belongs to a church.

These ruins also taught later builders. During the Renaissance, architects came to Rome to study ancient buildings. These wide concrete vaults were among the models they measured and drew. The ambition of new Saint Peter's Basilica, with its vast vaulted spaces, owes something to halls like this one. In that sense, the ideas of this building travelled far beyond the Forum.

Walk around to the side that faces the modern road, the Via dei Fori Imperiali. From there, you can see the basilica as part of the city around it. Cars and buses pass. Tourists stop for photographs. The back wall rises high above the pavement, plain and massive. This view shows how the ancient and the modern sit side by side in Rome. People drive to work past a building their ancestors raised more than seventeen centuries ago.

Before you move on, take one more look up at the arches. Notice how the light falls across the coffers and changes as clouds pass. Notice the small plants growing from the cracks in the brick. Two emperors fought over this building. An earthquake broke it. Popes and architects took pieces of it and ideas from it. And still these three arches stand above you. As you walk on along the Sacred Way, look back once. Try to picture the other half... and the giant who once sat inside.