Carnuntum was one of the main roman forts on the Danube frontier, and, in particular, on the Limes Pannonicus, a section of the Danube Limes. Carnuntum is a center of celtic origin, its name deriving from from “kar” or “karn” which means rock in Celtic. During late roman times, the castrum was used by emperor Valentinian I as the main springboard for his aggressive campaigns against the Quadi tribes, germanic people. Carnuntum had a legionary fortress, an auxiliary fort and was home to the Pannonian river fleet. The auxiliary fort hosted the Ala I Thracum, a cavalry regiment, which, as the name suggests, came from the roman province of Thracia, in modern day Bulgaria. Ruins of a large amphitheater built around the second half of the 2nd century AD, which could host around 12.000 spectators, are still visible today.
Additionally, a civil center developed around the forts, most probably inhabited by the family of the soldiers. In 308 AD the city hosted the Carnuntum conference, a diplomatic gathering between the main leaders of Diocletian’s tetrarchy. Emperor Valentinian rebuilt the military forts which had been destroyed by the repeated incursions of the Jazigi, a Sarmatian (Iranian) tribal group. After the death of Valentinian in 375 AD at the fort of Brigetio, in modern day Hungary, the forts of Carnuntum went into disrepair. Today’s emblem of the city is the so called Heidentor, a monumental archway erected next to the fort probably dedicated to the reunion of the tetrarchs under Diocletian or to Valentinian’s victories against germanic tribes.
The so called “amber road”, which can still be walked on, ran through the legionary fort in Carnuntum leading to Aquileia, Friuli Venezia Giulia and Rome. Memories of roman times are still strong, as many streets and hotels are named after roman emperors. Carnuntum remains the most ancient roman fort on the Limes Pannonicus, a true stronghold against barbarian hordes.