Forum of Constantine

Listen first. Tram bells clang along the rails behind you. Shop shutters rattle. Simit sellers call out over the traffic on Divanyolu. And in the middle of it all stands one dark column. Its stone is the colour of dried wine, scorched almost black in places. It is wrapped in iron bands like an old barrel. This is all that remains above ground of the Forum of Constantine, once the ceremonial heart of a new imperial capital.

To understand why this spot mattered, picture the city before it had its famous name. In the early fourth century, Byzantium was a modest Greek town on the tip of this peninsula. Then the Roman emperor Constantine chose it as his new capital. He expanded it far to the west and rebuilt it on a grand scale. The city was formally dedicated in the year 330 and soon carried his name — Constantinople.

Constantine placed his forum just beyond the old town walls, on the city's second hill. The choice was deliberate. The forum marked the place where the old city ended and his new city began. Unlike the rectangular squares of Rome, this one was round, or close to round. It was ringed by colonnades, with grand gateways where the main road entered and left. Standing here, a traveller passed from the past into the emperor's future.

That main road was the Mese, the great processional avenue of Constantinople. Emperors rode along it in triumph. Merchants, priests and soldiers walked it every day. Here is the first surprise for many visitors — the road still exists. The busy street at your feet, Divanyolu, follows much the same line. When you walk toward Hagia Sophia from here, you are tracing a route people have used for about seventeen centuries.

Now look closely at the column itself. The main shaft is built from huge drums of porphyry, a hard purple stone brought from quarries in Egypt. In the Roman world, purple was the colour of emperors. Porphyry was rare, difficult to carve, and reserved for imperial use. Raising a column of this stone in the centre of the forum sent a clear message. This city belonged to the emperor, and he intended it to last.

At the very top, there once stood a bronze statue of Constantine. Ancient writers describe it with a crown of rays, in the manner of the sun god Apollo. Historians still debate what this image meant. It may show a ruler balancing old Roman religion with the new Christian faith he supported. The statue looked out over the forum for centuries. Then, in 1106, a violent storm threw it down, and it was never replaced.

The ground beneath the column holds the second surprise, though this one belongs to legend. According to popular tales, Constantine buried sacred objects under the base. Stories mention the Palladium, a protective statue said to have come from Troy by way of Rome. Later Christian legends add relics such as baskets from the miracle of the loaves. No excavation has confirmed any of this. But these stories show how people saw the column — as a guardian of the city.

The forum around the column was once filled with monuments. Writers describe statues collected from across the Greek and Roman world, set among the colonnades. A senate house stood on one side. Over the centuries, fires, earthquakes and war wore it all away. The crusaders who sacked Constantinople in 1204 caused great damage to the city's monuments. Bit by bit, the square of marble disappeared beneath newer streets, shops and houses.

The column survived, but it suffered. After the Ottoman conquest of 1453, the city changed rulers but kept this landmark. Fire came again and again. The flames cracked the porphyry and blackened its surface. Ottoman builders added the iron hoops you see today to hold the damaged drums together. They also wrapped the lower part in a heavy masonry base. That is why English speakers often call this the Burnt Column.

The Turkish name is just as descriptive. Çemberlitaş means, roughly, the hooped stone — a name taken directly from those iron bands. The whole neighbourhood carries the name, and so does the tram stop beside you. It is a small reminder of how this city works. A Roman emperor raised the monument. Ottoman hands repaired it. And today, commuters use its name every morning without a second thought.

Turn around slowly and look at the neighbours. Just beside the column is the Çemberlitaş Hamam, a Turkish bath designed by the great Ottoman architect Mimar Sinan for Nurbanu Sultan in the sixteenth century. It still operates as a bath today. A short walk away rises the Nuruosmaniye Mosque, and beyond it lies one of the gates of the Grand Bazaar. Roman, Byzantine and Ottoman layers stand within a few minutes of each other here.

If you want to sense the size of the lost forum, use your imagination as a measuring tool. The open square stretched well beyond the edges of the modern plaza. Its colonnades would have curved through the buildings now behind you. The original Roman ground level also lies below today's street. Over time, the city simply rose around the column, layer upon layer, as rubble and new construction lifted the surface of everyday life.

Before you move on, stand still for one more moment. Let your eyes travel from the iron hoops up along the scarred purple stone to the empty top, where the emperor once stood. The trams keep passing. People hurry to the bazaar with shopping bags. Most of them do not look up. But you know now what this column marks — the place where an old town ended, and a new city began.