The End of a Metropolis – The Fall of Carnuntum

Carnuntum is one of the most significant archaeological sites in Central Europe. Over the course of several centuries, the city developed into a central political, military, and economic hub on the middle Danube. As a legionary garrison, the capital of the province of Pannonia Superior, and an important trading center, Carnuntum connected the Roman Empire with the regions north of the Danube. Nevertheless, a profound transformation began during late antiquity that ultimately led to the demise of the ancient metropolis. This process occurred neither suddenly nor for any specific reason, but was the result of long-term political, economic, and social changes in the Danube region.

Since the start of the 2026 season, visitors have been able to immerse themselves in the history of Carnuntum at the Carnuntum Experience: On a journey through the centuries, the transformation of this ancient metropolis — from its heyday to its eventual decline — is brought to life through impressive 3D visualizations. - © 7reasons 

As early as the late 3rd century, and especially in the 4th century, Carnuntum’s role within the Roman frontier system began to change. The empire’s political and military structures were undergoing profound transformation. Although the Danube frontier remained a central component of the Roman Empire’s defense, military strategies and administrative structures were increasingly adapted. At the same time, internal Roman conflicts, economic restructuring, and repeated attacks from the Barbaricum led to a gradual destabilization of the existing order.

Archaeologically, this transformation is clearly evident in Carnuntum. Many public buildings and infrastructure projects, which had been constructed during the city’s heyday in the 2nd and early 3rd centuries, lost their original function. Monumental structures were partially repurposed or abandoned. In some areas of the city, there was a significant reduction in building density, while other areas continued to be used. The late antique city was thus significantly smaller and functionally organized differently than the former urban center of the Imperial period.

AI-generated visualization of the ruined frigidarium in the Roman quarter - © Römerstadt Carnuntum (generated with ChatGPT 5.3)

In addition, there were repeated natural disasters that may have accelerated the city’s decline. In particular, the severe earthquake in the mid-4th century, which is also mentioned in historical sources, likely caused significant damage to the city’s buildings. Reconstruction apparently took place only partially and on a significantly reduced scale. Many buildings were not restored to their original grandeur, but were merely pragmatically repaired or abandoned altogether.

During the late 4th and early 5th centuries, signs of a fundamental transformation of Roman Carnuntum became increasingly evident. While some areas remained inhabited, others were increasingly abandoned. Archaeological findings show that parts of the former city were increasingly used as a quarry: building materials from Roman structures were quarried and reused for new constructions in the surrounding area. This process of so-called “spolia” reuse can be observed in many former Roman cities and often marks a transitional phase between urban use and final abandonment.

Excavation work in 2017 in the southern section of the villa urbana and the exposure of the 4th-century earthquake horizon - © N. Kirchengast 

With the collapse of Roman administrative and military structures in the Danube region during the 5th century, Carnuntum eventually lost its function as an urban center. One of the last written references dates from the year 433 CE, when the Western Roman commander Flavius Aëtius, as part of a political settlement with the Huns, ceded parts of Pannonia—including the area around Carnuntum—to them, marking the definitive loss of Roman control over the region.

Unlike some late Roman cities, no continuous late antique or early medieval successor settlement developed in Carnuntum. Instead, the former metropolis gradually fell into ruin, while smaller settlements in the surrounding area became new centers of activity.

Late Antique finds from Carnuntum: 5th-century jug (CAR-K-3206), belt buckle (CAR-M-2818), comb (CAR-OR-74), propeller-shaped brooch (CAR-M-3815), and cup (CAR-G-22) - © Landessammlungen NÖ

Even though Carnuntum ceased to exist as a city, its monumental ruins remained visible for centuries. Walls, foundations, and massive piles of rubble continued to shape the landscape of the Vienna Basin. Such impressive remains gave rise to numerous interpretations and legends as early as the Middle Ages. The ancient structures were often interpreted as “pagan”—a term used to describe everything Roman and thus pre-Christian. In folk traditions, this gave rise to stories about giants, lost cities, or mysterious structures from a time long past.

The Heidentor is featured in the Carnuntum Experience. To document the transformation of this historic monument, the Heidentor was recently included in Europeana’s EU campaign “Twin it!” - © 7reasons 

At the same time, however, the ruins served once again as a quarry for many centuries. Ashlars, bricks, and other building materials were systematically quarried from the ancient structures and reused in medieval and early modern construction projects. In this way, a part of Carnuntum lives on to this day in many buildings throughout the region—hidden within walls, foundations, and church structures.

AI-generated visualization of the ruined hostel and Villa Urbana. Residents of the remaining settlement areas are engaged in stone theft - © Römerstadt Carnuntum (generated with ChatGPT 5.3)

The long-term evolution of the landscape in the Vienna Basin is currently being studied as part of modern interdisciplinary research projects. One example is an Anthropocene project at the University of Vienna that analyzes the interactions between human settlement, environmental changes, and geomorphological processes over long periods of time.

Particularly revealing is the comparison between Carnuntum and Vindobona, the Roman predecessor of modern-day Vienna. Both cities arose at strategically advantageous locations along the Danube and controlled important crossings over the river. While Carnuntum, however, lost its urban function during late antiquity and eventually disappeared as a settlement, Vindobona continued to develop over the centuries. The Roman military camp gave rise to a medieval town, from which the modern metropolis of Vienna eventually emerged. This comparison shows that the “end” of a city is by no means inevitable. Rather, the long-term development of urban centers depends on a multitude of political, economic, and landscape-related factors.

Colored copperplate engraving of Petronell and surroundings after Matthäus Merian 1656 - © Land NÖ, APC Archiv

It was not until the 19th century that a new phase in Carnuntum’s history began. Archaeologists, historians, and natural scientists increasingly devoted themselves to researching the ancient city. Systematic excavations brought numerous buildings, streets, and archaeological complexes to light, providing for the first time a more comprehensive picture of the former metropolis. Today, Carnuntum ranks among Europe’s most important archaeological landscapes. Modern research projects, innovative educational formats, and spectacular reconstructions make it possible to experience and understand life in a Roman city in a unique way. 

Carnuntum thus exemplifies the dynamism of historical landscapes. Cities emerge, change, and disappear—yet their traces remain preserved in the landscape, in memory, and in the material remains. It is precisely this long-term perspective that makes Carnuntum an extraordinary field of research: as a former metropolis of the Roman Empire and, at the same time, as a vibrant site of archaeological research and education.