The Roman City of Claudivium Disappeared From Historical Records Almost 2,000 Years Ago. It May Have Been Hiding in Austria

Archaeologists in Austria have discovered the remains of a “large and meticulously planned” Roman city along the Danube River that managed to go undetected for nearly 2,000 years. Geophysical surveys conducted near the town of St. Pantaleon-Erla, in Lower Austria, revealed traces of the previously unknown urban area, which covered an estimated 62 to 75 acres.

The sprawling city appears to have been systematically laid out, with gridded streets and a massive amphitheater that could accommodate about 8,000 people. Researchers also discovered a large cemetery in the city’s northwest, filled with “countless graves, burial structures and burial mounds,” according to a September 23 statement. Some of these were large, which suggests that whoever was buried there was wealthy.

Together, the forts likely controlled a Danube crossing point near its confluence with the Aist River, a waterway that was important for trade with regions beyond the Roman Empire. Against that backdrop, the settlement appears to have been strategically important. Civilian settlements commonly sprang up near long-term Roman forts, providing goods and services to the troops stationed there.

But the researchers note that the size and organization of the newly discovered city is “unprecedented throughout the entire Roman Empire.” Archaeologists haven’t been able to definitively identify it, but they suspect that the city might be the remains of Claudivium, a place mentioned by Ptolemy, the astronomer, mathematician and geographer who lived during the second century C.E. Ptolemy’s coordinates broadly line up with the location of the settlement, as does his description of a river (possibly the Aist) flowing in from the north. Additionally, the name Claudivium disappears from historical records starting around 180 C.E., which aligns with the timeline of this city’s abandonment.

The site is located within the Danube Limes, a UNESCO World Heritage Site that spans nearly 375 miles of the Roman Empire’s Danube frontier. Since 2015, an interdisciplinary group of researchers has been exploring a roughly six-mile-long stretch of the Danube Limes between the Austrian towns of Enns and St. During the Roman era, the area formed the northern border of the province of Noricum.

Researchers think the settlement was founded around 80 C.E. and then abandoned roughly a century later. The archaeological evidence suggests that residents left in an “orderly, planned withdrawal,” according to the statement. Fortunately for researchers, the area was never developed—unlike many other Roman sites in the region—and is now used for agricultural purposes.