Archaeologists in Austria have uncovered evidence of a large Roman city near Stein, along the Danube River. The site includes an amphitheater with 8,000 seats and a fort designed for 500 soldiers. This discovery, revealed through ten years of geophysical surveys, was published in September 2026 by the University of Innsbruck. The city's size is much larger than that of a typical military outpost, suggesting it was a significant urban center in the region. Since 2015, a team of researchers has been studying about ten kilometers of the Danube frontier, using methods such as geophysics, aerial archaeology, and targeted excavations. The settlement in Stein was located near a river passage and the mouth of the Aist river, which served as a commercial route connecting to the Vltava and trade networks beyond the Roman Empire. The road network surrounding the auxiliary fort covers 25 to 30 hectares, an unusual scale for a garrison of only 500 men. The stone fort dates back to the 2nd century, with a wooden camp built before it. Geophysical surveys also uncovered an amphitheater with 8,000 seats, a size similar to that of Carnuntum, one of the main Roman cities in the area. To the northwest, researchers found a large necropolis with burial mounds and grand monuments, suggesting the presence of wealthy individuals. Along the southern edge of the city, three drying installations were discovered, possibly the remains of a brewery, indicating a level of craftsmanship beyond basic food supplies. The Roman city in Austria existed between approximately 80 and 180 AD and lasted no more than a century. No signs of violent destruction were found, suggesting the city was abandoned in an organized manner. Coins found at the site indicate the city was abandoned around the turn of 180 AD, coinciding with the end of the Marcomannic wars under Emperor Commodus, who succeeded Marcus Aurelius. Rome likely reorganized its frontier, with some artisans moving to Lauriacum, now known as Enns. Archaeologists found bronze tools and fibulae (decorative clasps) similar to those from Stein, linking the two sites. Lauriacum saw rapid growth after this time, becoming a major military center. In the 2nd century, the geographer Ptolemy mentioned a city called Claudivium in this part of the frontier. The coordinates and description of a river coming from the north match the location of the site and the Aist river. However, no inscription has yet connected the site to the name Claudivium. Some kilometers away, archaeologists have found the foundations of an unfinished legionary fortress at Albing, where builders had dug trenches and laid massive bases but never completed the walls. Future research may explain why this construction was abandoned and clarify the connection between the settlement and the ancient name Claudivium.