The Roman empire penetrated deep into Germany. But, after the time of Christ, Rome had to fight to maintain its frontiers along the Rhine, Main and Neckar rivers and north of the Danube.

Signs of Rome are easy for travellers to find in German cities. Several of these survived Rome and its medieval successor, the Holy Roman empire of the German lands. Certain sites retained their importance from one age to the next – medieval buildings rose over Roman foundations.

It is not hard today to find traces of Roman works in museums. Occasional monuments are in cities such Frankfurt, Worms, Koblenz, Wiesbaden, Bonn and Aachen. Many buildings in these places rest on Roman archaeology. Rural villas have been excavated and forts reconstructed, such as at Saalburg near Frankfurt and Römerpark Ruffenhofen near Dinkelsbühl.

But several places, through their standing monuments and archaeological collections, give glimpses into the depth and scope of Rome’s contribution to medieval Germany and the German nation that followed it.

It is odd that Germany’s Roman history has been so underplayed. In at least two ways Rome helped create a sense of Germanness – first by uniting tribes in resistance, then by providing inspiration for German kings and emperors.

Most of the Roman names of these cities survive. Roman names also appear in city street plans.

Cologne

Cologne is not a Roman city. Nowhere will we find a priceless preserved or restored Roman precinct with gates, baths and a forum. If this is what you are looking for, close this blog and search "Pompeii", or consider visiting Trier as the only German city with something approaching a suite of Roman monuments, or the recreations at Xanten (see below).

But, if you enjoy walking the streetscape of a historic city and observing how the ruins of a Roman power centre were steadily absorbed into the monuments of later ages, you will love Cologne. You will be able to view the fruits of a handful of site excavations and visit Roman remnants in a museum environment. You can even retrace the wall of Roman Cologne on foot with little trouble in about 90 minutes (Raven Guides explains how in its Cologne travel guide) or walk through a length of Roman sewer.

There was a Roman garrison town on the Rhine under the emperor Augustus. But Cologne became a city when the empress Agrippina, wife of Claudius, asked for her birthplace to carry the status of colonia, or city. With this came civic institutions, public buildings, a wall and a grid of streets.

Parts of Colonia Claudia Ara Agrippinensium still stand and many finds are in the Römisch-Germanisches Museum. Sections or foundations of the Roman city wall remain and can be followed by walkers with the right map. Bronze relief maps inserted into paving at various sites make the wall easier to follow, especially along the north side. The most complete Roman tower is the Römerturm, the city’s former north-west corner.

Cologne maintained much of the street plan of the Roman city, while new buildings sprung up on old sites. The cathedral, Germany’s mightiest, is no longer believed to stand on the remains of a temple to Mercury Augustus. But its early north wall did run along the city wall. The replica arch standing opposite the west portal is only part of what was the much larger and elaborate triple-arched and columned north gate. This aligned with the main north-south Roman street, known in most cities as Cardo Maximus (followed by today’s Hohe Straße).

The original inscribed central arch is part of the Römisch-Germanisches Museum collection (in 2023 in an interim exhibition at the Belgisches Haus in Cäcilienstraße). Monumental works such as the Poblicus Mausoleum and the Dionysus Mosaic (closed in 2023) are among the leading exhibits from Cologne’s physical culture. The rest are funeral monuments, personal and household items such as jewellery, coins, remnant artworks and inscriptions.

Offsite, but still part of the museum, are the footings of the Praetorium or governor’s residence, almost under today’s Altes Rathaus (town hall). These can be viewed today, along with a section of Roman sewer tunnel. Restored statues of prominent Roman and medieval figures associated with the city cover the Altes Rathaus tower.

The Rhine city wall stood behind today’s Rathaus. At the south end of today’s building, a city gate believed to have been dedicated to Mars opened to the Roman bridge across the Rhine. In Roman times an arm of the Rhine formed a long island that became the river port and a warehouse was built. Where the Romanesque church of Groß St Martin is today, visitors can stroll through the archaeology, which includes a Roman chapel that was the church's forerunner.

Christianity was officially recognised in the Roman empire early in the 4th century and Cologne became one of the early bishoprics. The church of St Severin is consecrated to an influential 3rd century bishop and patron of Cologne. The site of the so-called Capitoline temple (perhaps dedicated to Jupiter, Juno and Minerva) became a 7th century convent, then the site of the 11th century Romanesque church St Maria im Kapitol.

Other Romanesque churches rest on Roman foundations. The Cäcilienkirche (now a museum of medieval church sculpture) was built over a Roman bath complex. Another, St Ursula, was built over a Roman cemetery, while St Gereon was consecrated to a Roman martyr of the so-called Theban Legion.

Trier

In Trier today, it's possible to sense some of the magnificence of Roman times inside Constantine's rebuilt basilica, walking through the Porta Nigra, or exploring the imperial baths and amphitheatre.

Trier preserves Germany’s clearest signs of Rome. The “oldest German city” (Neuss was founded about the same time) was for a while number two in the Roman empire. Late in the 3rd century, under the Tetrarchy system, it was effectively the centre of the Western Roman empire.

Many of the Roman settlements in Germany were in the Rhine frontier zone, stretching into what were the provinces of Gaul. Along the Moselle lived the Treveri, a tribe that was an obstacle to Roman ambitions. The Romans bridged the river and established a town called Augusta Treverorum.

It was not easy to bring the Treveri to heel. But when they did bend to Roman will, the Treveri became good Roman citizens in a lively city named after them. The city grew to a population between 70,000 and 100,000.

Constantine, the first Christian emperor, was based in Trier early in the 4th century and built some of the structures that stand today. His palace – today restored as the Konstantin-Basilika – is the largest hall from Classical antiquity still standing.

Constantine left Trier before his vision for the city was realised. He reunited the Roman empire with the sword and founded a new capital, Constantinople.

An amphitheatre, the foundations of the Moselle bridge and the city’s north gate Porta Nigra all survive from the Roman period, some much altered. The most impressive of the survivals of the city’s bath complexes are the ruins of the Kaiserthermen, which visitors can explore.

The city walls stretched from the Porta Nigra on the line reconstructed in the Middle Ages, along the Moselle banks to the bridge. But the Roman city was much larger. The wall swept around the city's southern precincts to partly enclose the amphitheatre. Here, south-west of the city centre, the entrance formed a city gate.

Finds including monuments and beautiful mosaics are in Trier’s Rheinisches Landesmuseum. Also in the museum is a superb model of Augusta Treverorum with its street grid. At Trier’s zenith affluent families lived the Roman life in nearby country villas. A 20m column still standing at Igel indicates their wealth and depicts daily scenes. A painted replica is in the museum courtyard.

Constantine’s initiatives elevated Trier’s place in Christendom. He sent his mother St Helena to the Holy Land and she returned with a tunic now venerated as the Robe of Christ and nails from the Cross. These are today in Germany’s oldest cathedral, the Dom St Peter, which rests on the site of a Roman building complex that included two basilicas. Only the nails can regularly be viewed.

Next to the cathedral, on the foundations of the second Roman basilica, is Germany’s first Gothic church, the Liebfrauen-Basilika.

Trier began to decline in the 4th century and the Roman soldiers departed or disappeared into the local peoples. But the city’s symbolic importance remained and lent it authority under its new lords, the Franks. The 10th century Marktkreuz, signifying the importance of the town market, was set up on an old Roman pillar in the Hauptmarkt.

Xanten

Xanten is where Rome is recreated. Today, on the Rhine not far from the Dutch border, a small German city rejoices in its past.

Apart from its examples of medieval architecture, Xanten has a proud memory of an important Roman fortified city that has been partly resurrected as an archaeological park. For four centuries it was one of the most important Roman centres of northern Europe.

About the birth of Christ the Roman general Drusus built the legionary camp Castra Vetera as one of his main operational bases along the German frontier. It had as many as 10,000 legionaries and became a base for Roman river traffic.

Germanic tribes got the better of Roman forces about 70CE and Castra Vetera was wrecked in a legionary rebellion. But a generation afterwards the Romans built on the Rhine bank a new, walled Castra Vetera. The emperor Marcus Ulpius Traianus, with customary imperial modesty, renamed the city after himself and granted city rights in 110. Colonia Ulpia Traiana joined the forerunner of Cologne as a Roman commercial centre in lower Germany, which the Romans named Germania Inferior.

Today Xanten has as its Roman legacy LVR-Archäologischer Park, a part-reconstruction of Colonia Ulpia Traiana a few minutes’ walk from the town. It has expanded in recent years to be one of the largest open-air museums in Europe at 60 hectares.

The reconstruction traces a large area of the street grid and the city wall with gates and towers is in the building process. The parapets and reconstructed houses are accessible to visitors. The city amphitheatre is largely recreated, the most complete example of an amphitheatre in Germany.

Some Classical columns of the so-called Hafentempel have been resurrected and excavated areas of the baths complex have been sheltered by a vast glass superstructure built in imitation of Roman designs. The attached LVR-Römer Museum contains an exhibition of finds from both Castra Vetera and its successor, including military hardware. Archaeological work continues on parts of the Roman site.

In the 4th century, all over its empire, Rome met Christianity. This acquaintance was not always peaceful. Remembered today in the former Roman cities of Cologne, Bonn and Trier is the legend of the Theban Legion, 360 Roman soldiers martyred for their determination to stand on their faith and refusal to sacrifice to Roman gods. The Colonia Ulpia Traiana legionary St Viktor, who was executed in the amphitheatre, is celebrated in the 13th century cathedral, built over a 6th century monastery. 

Mainz

Mainz is one of several German places where Roman monuments still stand. But clear remains of a large aqueduct and a Roman temple are found nowhere else in the country. Mainz is also a place to see and compare Roman ships. The Roman bridge at Mainz is known from surviving medals and piers from it have been found.

It is also the site of an extraordinary monument, the Drususstein, possibly set up by Roman troops to honour Drusus, their general. About 20m high, the circular stone memorial was once cased in marble. It stands today immediately south of the Zitadelle, Mainz’s 17th century fortress. The park Wallgrünanlagen follows the line of the Roman wall and a section called Drususwall runs parallel to the street Am Fort Elisabeth.

The Roman-Celtic Mogontiacum was made up of settlements and a military camp (castrum) on a hill that was probably garrisoned by two legions – up to 12,000 soldiers. Mogontiacum was destroyed by revolting Batavian troops in the year 69 but the legions defeated them and refortified the hill.

Gateway pedestals celebrating the victory were found on the hill, now called Kästrich. The footings of a fortress gateway remain and the street names of the area commemorate Roman personalities.

The legionary camp was supplied with water by a 9km aqueduct built about the year 70. This was a double-level arched construction up to 30m above the ground. Today the remains of the aqueduct pillars stand along An den Römersteinen, still several metres high, with information boards that include construction sketches.

An area of walled town stood on the south-west bank of the Rhine, along with a trading port and grave fields. It became the provincial capital of Germania Superior about 80CE.

The existence of a Roman naval base and a merchant presence is confirmed by finds of ships that are now in the Museum für Antike Schifffahrt. Reconstructions are among exhibits of the remains of a variety of military and civilian vessels. The museum is expected to reopen in 2024 after a reorganisation.

The 1st century Jupitersäule, an ornate column that would have stood more than nine metres high, was once topped by a two-metre bronze statue of Jupiter. Reliefs on the limestone column and pedestal show other deities and there was a sacrificial altar. The monument was set up in honour of the emperor Nero by Roman citizens, although the inscription was defaced after Nero’s suicide. The pillar art shows Celtic influences and must have been the gift of a prosperous Roman-Celtic trading population.

In 1905 the column was found shattered and buried and the pieces were collected and studied. Parts are reassembled in Mainz’s Landesmuseum. Replicas were set up in front of Mainz’s Deutschhaus assembly building and the Saalburg fort reconstruction near Frankfurt. Others are known from areas along the Rhine.

These are fascinating discoveries. But a visit to the museum on the site of the former temple of Isis and Magna Mater (also known as Cybele) is a unique trip into an alien world. The site was uncovered by excavations for a shopping centre two decades ago. The museum is accessible on the lower level.

Museum exhibits include inscriptions, everyday objects such as bowls, plates and lamps (probably used in rites) other ritual objects including statuettes, coins and the rectangular foundations of the temple.

Rome assimilated the Isis deity from Egyptian culture. But this is not the only sign of Egyptian influence. A painting of the death god Anubis was found, along with food offerings such as dates and figs from the east end of the Mediterranean. Cybele’s origins are in the area of modern Türkiye. Rome’s influence on Germany is clear, but so are the influences absorbed by Rome.

A theatre 116 metres in diameter has been uncovered next to the rail station named after it. It would have accommodated up to 12,000 people. But it fell into disuse in the 4th century, when the stone was taken to build the city wall.

About 260 Rome took over the right bank of the Rhine and established the frontier fortifications known as the upper Limes, the remains of which are listed as world heritage sites by UNESCO. From this period comes the sandstone arch Dativius-Victor-Bogen, more than 6m high, set up in honour of Jupiter and the emperor by the regional councillor Dativius Victor. Fragments were discovered during demolition of Mainz’s medieval wall. A reconstruction is at Ernst-Ludwig-Platz near the Römische-Germanisches Zentralmuseum.

The keystone shows Jupiter and Juno in relief, Jupiter with his foot on the world globe. The monument has a typically provincial style and was no grand arch, rather the centrepiece of a portico.  After several decades the fragments found their way into the Roman fourth century town wall and the later medieval wall. The original arch is in the Landesmuseum. 

Augsburg

A pine cone, the symbol of Augsburg, sits atop the city’s elegant Renaissance Rathaus. The inspiration came from Rome, where the pine cone was a popular symbol of fertility and prosperity. It had a religious significance for many, but for Augsburg the historical significance is greater.

Augsburg was founded as a military camp at the order of the emperor Augustus in 15CE and named Augusta Vindelicorum. Later, the emperor Claudius built the military road Via Claudia Augusta through it to the north.

In the first century Augusta Vindelicorum became the provincial capital of Raetia. About the same time the pine cone was a prominent image in Rome: a bronze fountain in that shape appeared next to a temple in the city and a district was named for it. The pine cone is now in the Vatican precinct.

Apart from in its name, the signs of Roman occupation are not prominent in Augsburg as in Trier, Cologne, Mainz or Xanten. Attacks by the Huns and others in subsequent centuries mean there are few visible Roman remains apart from the archaeology.

But the Domplatz around Augsburg’s 11th century cathedral is something of a time capsule, and here the Roman past is clear. The cathedral is on the site of a 4th century building and fragments of Roman buildings, columns and sculpture are on display. These include a pine cone and a complete column with a pine cone mounted on top.

A trove of Roman artefacts including mosaics, sculpture and stone memorial pieces are displayed in an interim museum at the city’s armoury. One highlight is a bronze horse's head.

On the ground floor of the Rathaus main hall is a room of Augsburg replica exhibits, including Roman objects.

The Roman presence ended in the 4th century, but Augsburg was not finished with Rome and emperors. It became a free imperial city under the Holy Roman emperor in the 13th century. The Renaissance fountain Augustusbrunnen, depicting the emperor as founder, faces the Rathaus and its pine cones on Rathausplatz.

Regensburg

Regensburg’s importance goes back even further than its early Frankish city site. It was an ancient Celtic settlement and a Roman fort under Vespasian. In the 2nd century a legionary camp called Castra Regina was built for the emperor Marcus Aurelius. Parts of Castra Regina can be seen at Ernst-Reuter-Platz, east of Maximilianstraße and not far from the today’s central rail station.

The fortifications, designed to protect about 6000 soldiers, were begun in the year 179 and strengthened about 300. Their significance, however, lasted long after Rome because Regensburg, then known as Ratisbona, grew up largely within them and later buildings were built along the wall line. Castra Regina was the northern frontier fort against the tribes of Germania.

The Porta Praetoria, on Unter den Schwibbögen near the cathedral precinct, was the north gate of the Roman legionary base Castra Regina. The simple stone arch is next to part of a circular Roman bastion.

Visitors can walk at Roman street levels and through remains of the medieval convent and city foundations on an underground tour called Document Niedermünster. Tours can be joined through the Infozentrum at Domplatz 5. Information boards are in English.

At Neupfarrplatz, the underground museum Document Neupfarrplatz uncovers the former Jewish quarter and archaeological layers from the Roman period unearthed in the 1990s. Again, admission is by tour only.

Regensburg’s Historisches Museum collection includes finds from Castra Regina. There is a model of Porta Praetoria’s likely appearance, a gate slab from one of the portals, and reconstructions of Roman life.

There is also a Classical temple near Regensburg, but it is a comparatively recent nod to the city’s past. Walhalla was built by the Bavarian king Ludwig I in the 19th century as a hall of honour to those he viewed as Germanic heroes of the past, including the fields of music, literature and science. 

Passau

Passau, on the Austrian border where the Danube, Inn and Ilz meet, has benefited over almost 2000 years from foreign influences. Some were carried there on the rivers, following an ancient salt trade.

But the zone was also a Roman frontier. The Romans, who always understood the value of location, built four fortifications in succession. In the 1st century a fort and Customs station was established on land now occupied by Passau's old town. A fort called Boiodurum was on the south Inn bank, part of the Roman province Noricum, lasted into the second century, with a settlement (vicus) nearby.

A quadrangular fortified camp near the spit of land now called Dreiflüsseck was built about 180BCE, served by a wharf on the Danube's southern bank. Another fortification was in the Ludwigsplatz and Nibelungenplatz about the same time. Both these were in the province of Raetia. A town developed and lasted into the late Roman period.

Apart from remains excavated under Kloster Niedernburg, there are few signs of the large fortresses today, except in the city’s name. This comes from the name Batavis, coming from the Batavian troops who were based there. But a much smaller fort left a clear footprint.

Across a footbridge from the old town, on the south bank of the Inn, are Roman and medieval remains. A pentangular fort, Boiotro, appeared on the south bank of the Inn late in the 3rd century and lasted into the late Roman period, when it burned. The foundations of the rounded towers of the oddly shaped fort can be seen today on the site. RömerMuseum Kastell Boiotro, preserving Roman finds, is on the site.

Foundations of a Roman sentry post (Burgus, signposted Wachturm) are accessible under an open roof on Wr Strasse, on the southern Danube bank. The kiln remains inside are medieval. The site is next to the Haibach sewage treatment plant 1.5km east of Passau.

For more on German city architecture, check out the Raven Travel Guides Europe blogs on beautiful Renaissance Augsburg, Baroque German cities, medieval German cities and Hanseatic Renaissance cities.