The Amphitheatre, on the outskirts of the modern, as well as the Roman town, was built into the very slope of the Petrisberg, not far away from the Weinlehrpfad. The theatre was built about 100 A.D., richly decorated during the following centuries.
Its western half held the imperial box and seats reserved for highranking civil servants. Its main entrances, to the north and south, had originally been provided with magnificent facades with ample space for three passages and vaulted entrances. On its western ide, two smaller doors led upwards and to the tiers.
The arena had room for roughly 20000 spectators.In the 4th and 5th centuries the Amphitheatre was at the same time a town gateway, so that the north entrance lay inside and the south entrance outside the town walls. The gate structures and the remaining walls were used for quarrying in the Middle Ages and also later on.