Servian Wall

Put your hand on one of these blocks. The stone is soft and slightly gritty, a dull yellow-brown, warm in the afternoon sun. Behind you, buses brake and hiss. Suitcase wheels rattle across the pavement towards Termini station. And here, in the middle of all that noise, stands a line of stones that Romans stacked more than two thousand years ago. This is the Servian Wall, the first great defensive circuit of ancient Rome.

The name comes from a king. Roman tradition said the wall was built by Servius Tullius, the sixth king of Rome, in the sixth century before Christ. That is the story the Romans told about themselves. Archaeologists see it a little differently. Some earlier earthworks and defences may well go back to the age of the kings. But most of the masonry you see today belongs to a later moment, in the early fourth century before Christ.

That later moment was a disaster. Around 390 BC, an army of Gauls, Celtic warriors from the north, defeated the Romans and entered the city. They plundered Rome and left only after they were paid. For a proud young city, it was a deep shock. The Romans responded in a practical way. They built a wall strong enough that no raiding army could simply walk in again. The blocks in front of you are part of that answer.

Look closely at the stone itself. It is tuff, a volcanic rock made from compressed ash. Central Italy has plenty of it, because ancient volcanoes once covered the region. Tuff is easy to cut when fresh, and it hardens with exposure to air. Here is a detail most visitors miss. Much of this stone came from quarries near Veii, an Etruscan city north of Rome. The Romans had conquered Veii only a few years before the Gauls arrived. So the wall was built, in part, with stone from a defeated neighbour.

Notice how the blocks are laid. They are long and rectangular, set in alternating rows. In one row, the long side faces you. In the next row, the short end faces you. Builders call this headers and stretchers, and it locks the wall together. There is no mortar here. The weight of the stones and the precision of the cutting hold everything in place. Run your eye along a single course, and you can follow the work of ancient masons, block by block.

Now imagine the whole circuit. The wall ran for roughly eleven kilometres around the city. It wrapped around the famous seven hills, including the Capitoline, the Palatine and the Aventine. In places it stood around ten metres high. Gates opened along its length, where roads left the city for the countryside. On the most exposed side, where the land is flat, the Romans added a huge earthen rampart behind the wall and a deep ditch in front of it. They called the rampart the agger.

That flat ground is where you are standing now. The Esquiline, Viminal and Quirinal hills merge here into a broad plateau. There were no cliffs or valleys to slow an attacker, so this was the weakest point of the city. That is why the defences were heaviest here. It is also a strange twist of history. The most vulnerable stretch of the wall became the place where one of its longest surviving sections remains, right beside the main railway station of modern Rome.

The wall did its job for a long time. It was repaired and strengthened several times during the long wars of the Roman Republic. In the third century before Christ, the Carthaginian general Hannibal marched across Italy and won great victories against Roman armies. Yet he never took the city itself. Historians debate exactly why. But a fortified Rome, with walls like these, was a very hard target for an army far from home.

Then Rome grew too large for its own wall. As the Republic became an empire, the city spread far beyond this circuit. Houses, gardens and public buildings covered the old defences. For a few centuries, Rome felt safe enough that it barely needed walls at all. Only in the 270s, under the emperor Aurelian, did Rome build a new and much larger ring of walls. Those Aurelian Walls are the ones you see around the city today. This older wall faded into the urban fabric.

Here is the second surprise. Fragments of the Servian Wall survive in some unexpected places. Inside Termini station area, a section of the wall is preserved right inside a fast food restaurant. People eat burgers beside stones from the fourth century before Christ. Other fragments appear in courtyards, in basements and beside busy roads across the city. Many Romans walk past them every day without a second glance.

If you continue exploring, the Aventine Hill holds another well-preserved stretch. It lies on a quiet residential street, among gardens and old churches. That section shows later repairs, including an arched opening that scholars think may have been made for defensive artillery, such as a catapult. On the Esquiline, the Arch of Gallienus stands on the site of an old gate in this wall. Each fragment gives you a different piece of the same long circle.

Think for a moment about what this wall meant to the people inside it. For ancient Romans, the line between the city and the outside world was not only military. It was also legal and religious. Certain things belonged inside the city, and others had to stay outside. Walls like this one made that boundary visible and solid. When a Roman traveller came home and passed through a gate here, they knew they had returned to Rome.

Before you leave, take one more look. The station clock, the traffic and the tram lines all belong to today. The worn tuff blocks belong to a city that was small, frightened and determined to survive. Notice the cracks, the rounded edges and the darker patches where rain has run for centuries. As you walk away into the noise of modern Rome, you are crossing a line that the first Romans drew to protect themselves.