Umbilicus urbis Romae

Stand still for a moment and look down. At your feet, behind a low barrier, sits a small round stump of brick. It is weathered and rough, and it is the colour of dry terracotta. Tourists walk past it every few seconds without a glance. The great arch nearby takes their attention, and the columns of the temples rise all around. Yet this modest ring of brick once carried an enormous idea. The Romans called it the Umbilicus urbis Romae... the navel of the city of Rome.

The word umbilicus means navel in Latin. A navel is the point where life begins, the centre of the body. For the Romans, this spot marked the symbolic centre of their city. And because Rome saw itself as the centre of the known world, the navel of the city was, in a sense, the navel of everything. The Greeks had a similar idea. At Delphi, their great sanctuary of Apollo, a carved stone called the omphalos marked the centre of the earth. Rome, it seems, wanted its own.

Take a look at where you are standing. This is the north-western corner of the Roman Forum, the old political and religious heart of the city. Just beside you rises the Arch of Septimius Severus, a triumphal arch built for an emperor in the early third century. Close by is the Rostra, the speakers' platform where Roman orators addressed the crowds. Behind you, up the slope, is the Capitoline Hill. This corner was crowded with meaning. Everything important happened within a few steps of here.

The brick remains you can see today are usually dated to the same period as the arch, around the early third century. Archaeologists recognise the building style of that time in the brickwork. But the idea of a sacred centre is far older than these bricks. The name itself appears in late Roman lists of the city's monuments, written in the fourth century. So the brick stump is a late version of something the Romans had honoured here for a long time.

Here is the first surprise. Very few written sources describe the umbilicus in detail. Scholars still debate exactly what it looked like when it was complete, and what rituals took place around it. Some imagine a small round shrine or a decorated monument rising above this base. Others are more cautious. What survives is the core, the inner structure, stripped of whatever marble or decoration once covered it. You are looking at the skeleton of a monument, not its face.

Some historians link this spot to an even older and stranger idea — the mundus. Ancient writers describe the mundus as a sacred pit that connected the world of the living with the world of the dead. According to one tradition told by the Greek writer Plutarch, when Romulus founded Rome, he dug a round pit. Settlers from many places threw in a handful of earth from their homeland. Whether the umbilicus and the mundus were the same place is uncertain. It remains a theory, not a proven fact.

The ancient sources also say that the mundus was opened only on a few special days each year. On those days, Romans believed the spirits of the underworld could pass into the city. Public business was avoided. People were careful. It is a powerful image — a hole in the ground at the heart of Rome, a door between two worlds. But remember, the connection with this particular brick structure is a scholarly suggestion. It is a story worth knowing, and it is best held lightly.

Now for the second surprise. The umbilicus had a neighbour with a rival claim. Not far from here, near the Temple of Saturn, the emperor Augustus set up the Golden Milestone in 20 BCE. This was a column covered in gilded bronze. It was meant to list the distances from Rome to other cities of the empire. The great Roman roads were measured from the city's gates, but the milestone made a clear public statement. Rome was the point from which the world was measured.

So this small corner of the Forum held two symbols of centre. One was religious and ancient, a navel tied to the birth of the city. The other was political and practical, a golden marker for an empire of roads. The famous saying that all roads lead to Rome came much later, in the Middle Ages. Still, you can feel its roots here. Standing between these two markers, a Roman citizen stood, quite literally, at the middle of their world.

Look again at the shape of the ruin. It is round, built up in layers of flat red bricks bound with mortar. The Romans were masters of this technique. They poured strong concrete and faced it with brick, which allowed them to build fast and build big. Here, the same skill was used for something small and symbolic. Notice how the surface is uneven, with gaps where facing stones have been lost. Over the centuries, many monuments in the Forum were stripped for building material.

After the fall of the Western Roman Empire, the Forum slowly changed. Temples became churches or ruins. Earth and rubble built up over the old pavements. For centuries, cattle grazed here, and people called the area a cow pasture. The umbilicus vanished under the soil like much else. It was only brought back to light through excavations in more recent centuries, as archaeologists uncovered the old level of the Forum. What you see now sits much lower than the medieval ground once was.

Take a moment to listen. Around you there is the shuffle of footsteps on gravel and stone, the murmur of a dozen languages, perhaps a guide's voice carrying across the ruins. Swallows and gulls cross the sky above the Capitoline. On a warm day, the stones give off a dry, dusty heat, and the air smells faintly of pine and sun-baked earth. People from every corner of the world gather in this small space. In a strange way, the navel of Rome still draws the world toward it.

Before you move on, look once more at the humble ring of brick. It does not shine like marble or tower like the arch beside it. It asks you to imagine. Picture the voices from the Rostra, the smoke from altars, the citizens crossing the Forum on business. Then lift your eyes to the arch, the temples, and the hill above. As you walk away, you are walking out from the centre, just as every road once did.