The little market town of Petronell (Carnuntum), with a population of 1250, on the right bank of the Danube, can look back on a long history spanning almost two thousand years. Although the earliest finds made in the region date from the Late Stone Age, it was 9 AD when the Romans founded the legionary fortress of Carnuntum about 2km/1.25mi east of the present town. The name "Carnuntum" is of Illyrian origin and means "stone" or "fortified place". Between 69 and 79, under Emperor Vespasian, it grew into a fortified military base with a harbor. During its heyday under the Emperors Hadrian and Marc Aurel Carnuntum had a population of more than 60,000, was an important trade and traffic center and formed the east-west route along the river as well as being on the "amber road" running north to south along the eastern Alps.
The Roman civilian settlement which has been uncovered to the west of present day Petronell boasted some magnificent villas, large functional and welfare buildings and sophisticated plumbing and drainage systems. Carnuntum was the capital of the Roman province of Upper Pannonia, and it was here that Septimus Severus was appointed Emperor and Diocletian called an imperial conference. The camp lasted until 375 before being razed by the invading hordes. The excavated Roman town has been made into an open-air museum. Visitors can see foundations of dwellings, the ruins of a palace built in the first half of the second C., and owned by the Roman governor, with remains of the central heating systems, cellars, bathrooms and marble cladding, the fourth C. Heidentor ("Pagans' Gate"), over 20m/65ft high, and the second C. amphitheater, discovered in 1922, which would have seated 15,000 spectators in seats only 4m/13ft above the arena. Finds relating to the plumbing system in the auxiliary castle and to the burial ground can be viewed in the new Petronell-Carnuntum Museum on the eastern edge of the town.
Standing alone some 10 minutes' walk to the south of the Petronell (Carnuntum) amphitheater is the Heidentor ("Pagans' Gate"), the remains (14m/46ft high) of a Roman triumphal arch, originally with four gates, built in the fourth C. A.D. in the reign of Emperor Constantine II. Of the four massive pillars which bore a groin vaulted roof only two remain, linked by an arch.
500m/550yds farther beyond the Petronell (Carnuntum) Legionary camp and town to the northeast is the Amphitheater I, built c. 180 AD, which had seating for 8,000 spectators (occasional open air performances). The amphitheater has two entrances, and in the arena is a square basin which provided drainage. To the north a vaulted walkway leads down to the Danube. Under the ambitious "Carnuntum Archaeological Park" scheme it is planned to carry out a partial reconstruction of the amphitheater.
Considerable remains of the civilian settlement have been uncovered in Petronell (Carnuntum). The amphitheater to the south of the modern road, known as Amphitheater II, is an elliptical building constructed in the second C. A.D., with seating for 15,000. To the east and west there were probably cages and pits for the animals. Having been buried under layers of rubble and earth for centuries, it was rediscovered in 1923-30 and partially rebuilt.
In the civilian district of Petronell (Carnuntum) are a number of buildings and other remains, discovered by means of aerial photographs or individual finds, and these still await detailed investigation; they include graveyards, palaces and ancient roads.
East of Petronell lie the Roman legionary camp and town (Canabae). The remains of the military fortress of Carnuntum, which was some 475m/520yds long and 335-400/370-440yds across, have been partially uncovered. (The main road between Vienna and Hainburg (B9) cuts right through it). Near the Danube-Marchauen nature reserve will be found the "porta principalis dextra" (right hand camp gate). In the northeastern corner of the camp a sewage canal, which crossed a water pipe, has been preserved. When excavating about 1km/0.75mi to the west of the legionary camp a second auxiliary camp was found, together with a bath complex.
To the west of the Schloss Petronell will be found the Great Baths (also known as the "Palace Ruins"), a Roman building measuring 104m/114yds by 143m/156yds, used in part as thermal baths. Excavations have revealed central heating and sewerage systems, as well as remains of marble cladding and wall paintings.