Isca Dumnoniorum

Put your hand flat against the old city wall and feel the stone. Some blocks are dark and rough, almost purple-grey, full of tiny holes. Others are a warm, crumbly red. The difference is not decoration. It is a record of who built the wall, and when. Beneath the cafés, cathedral bells and shopping streets of modern Exeter lies a Roman town. The Romans called it Isca Dumnoniorum. This walk is about that buried town, and the many places where it still breaks the surface.

Start with the name, because it holds the whole story in two words. Isca comes from a Celtic word linked to water. It almost certainly refers to the river below the city, which we still call the Exe. Dumnoniorum means 'of the Dumnonii'. The Dumnonii were the native people of this far south-western peninsula, the land we now call Devon and Cornwall. So the name means something like 'Isca of the Dumnonii'. It is a Roman label placed on a British landscape.

The town did not begin as a town. It began as a fortress. In the middle of the first century, a few years after the Roman invasion of Britain in the year 43, the army arrived on this ridge. The Second Legion, known as the Second Augusta, built a legionary fortress here. A legion was a force of several thousand professional soldiers. Think of a self-contained military city, with barracks, granaries, workshops and a headquarters, all laid out on a strict grid.

Why here? Stand on high ground in the city and the answer becomes clear. The ridge rises above the river, close to a point where the Exe could be crossed. From here the army could watch the routes into the south-west. Isca also sat at the western edge of firm Roman control. Beyond it lay the moors and the rugged country of the Dumnonii. For a time, this was one of the furthest outposts of the empire in Britain.

Now for the first surprise. Under the lawns of Cathedral Green, archaeologists found the legion's bath-house. They excavated it in the 1970s and uncovered the remains of a large and well-built bathing complex. Roman soldiers bathed as a daily routine, moving through warm and hot rooms heated from below the floor. After the dig, the remains were carefully covered over again to protect them. So when you walk across the grass near the cathedral, a Roman bath-house rests just below your feet.

The soldiers did not stay long. Within a few decades, the Second Augusta moved on to a new base in South Wales. That fortress, at Caerleon, carried the same name, Isca. It sat beside a different river, the Usk. So Roman Britain had two places called Isca, both linked to the same legion. When the soldiers left Exeter, the site did not fall empty. Instead, it began a second life.

The fortress became a civilian town, the capital of the Dumnonii. Rome often governed through local communities like this. A tribal territory was given a central town, with Roman-style buildings and local leaders who ran its affairs. In Exeter, a forum and basilica were built in the heart of the town. The forum was an open public square for markets and meetings. The basilica was a large hall for law and administration. Part of this civic centre was built over the old military bath-house.

Think about what that means for the people living here. Native families from the surrounding countryside could come to town to trade, to settle disputes, and to see Roman ways up close. Roman pottery, coins and household objects have been found all across the city. Some of them are now on display in the Royal Albert Memorial Museum, close to the city centre. The museum is a good place to see the small, personal objects of Roman Isca, if you want to continue the story indoors.

Now return to the wall, because this is the part you can touch today. Late in the second century, or early in the third, the town was enclosed by a stone wall. Its line ran around the hilltop for around two kilometres. Here is the second surprise. A large share of that circuit still stands. Exeter keeps one of the most complete sets of Roman town walls in Britain. Much of what you see has been repaired many times, but the route is the Roman route.

This is where the colours of the stone matter. The dark, pitted blocks are a volcanic stone, quarried locally. Some of it came from the hill where Exeter's castle later stood, an area called Rougemont, which means 'red hill'. Many of the warm red stones belong to later centuries. Medieval builders patched and raised the wall using a red local stone. So a single stretch of wall can carry Roman work at the base and medieval repairs above. Look for the line where one kind of stone gives way to another.

For good views of the wall, many visitors head to Northernhay Gardens and Rougemont Gardens. These green spaces sit against some of the best-preserved stretches. Other sections run behind car parks, along quiet lanes, and beside busy roads. Exeter's city council has set up a walking trail around the circuit, with information panels along the way. Following it gives you a real sense of the Roman town's size. You might be surprised how compact it feels. The whole walled town would fit comfortably inside a short evening stroll.

The Roman street plan has mostly faded, but the town's shape still guides modern Exeter. The main gates of later centuries sat roughly where Roman gates once stood. Some of the city's principal streets still follow lines that led into the Roman town. The cathedral itself rises within the old walled area, close to the site of the forum. Layer by layer, each new Exeter was built on top of the one before. The ground level of the city rose as a result.

What happened when Roman rule ended in Britain, early in the fifth century, is far less certain. Town life in many parts of Britain declined, and Exeter was probably no different. The written record for this period is thin, and archaeologists still debate the details. What we do know is that the walls lasted. Later generations reused them again and again. For more than a thousand years, the Roman circuit defined the edge of the city.

So as you stand here, take a moment to look again at the stone in front of you. Notice the holes in the dark volcanic blocks. Notice the softer red stone above it, worn smooth by centuries of rain. Listen to the city around you, the traffic, the footsteps, perhaps the cathedral bells. All of it sits inside a line drawn by Roman soldiers almost two thousand years ago. When you walk on, keep an eye out for the wall. It appears where you least expect it.