Built: Previous building at the beginning of the 1st century AD. The remains of the walls visible today date from later, around 310 AD.

The predecessor to the stage theater was probably built at the beginning of the 1st century AD. It was likely used as a gathering place for civil commemorations for the deceased general Drusus, whose honorary tomb had been erected only about 340 meters away on what is now the citadel.

Representatives of the 60 Gallic local authorities met here for this purpose. Mogontiacum – the capital of the Roman province of Upper Germania – was thus a political pilgrimage site for Germania and Gaul, where the common Roman roots were commemorated every year.

In the Middle Ages, work probably began on removing more and more stones from the theater building. The theater fell into ruin. With the construction of the citadel in the mid-17th century, the area was leveled and fell into oblivion. Parts of the Roman walls were used to build the Albani bastion in the protective wall. Today, it is easy to see where the Roman walls end and the 17th-century bastion begins.

The theater consisted of a stage and a semicircular auditorium. The ascending rows of seats were built into the hillside and could accommodate around ten thousand visitors at the time.

The walls are made of Roman cast concrete (opus caementicium) and were only clad with small ashlars on the outside. The Romans inserted double layers of brick slabs for stabilization.

In 2005, under the direction of the then state archaeologist, the first five rows of seats were erected as a wooden structure in the form of semicircular, ascending seating steps. This structure became increasingly dilapidated and rotten, posing an acute risk of collapse. As a result, the balustrade elements were renewed in 2017 so that guided tours and smaller events could take place again.

In 2016, the four-meter-high stone wall on platform 4 was demolished. It has since been replaced by a glass front. Whether arriving or departing, travelers now have an unobstructed and impressive view of the relics of the Roman theater. And thus of the time when Mainz was still called Mogontiacum.

By the way: Have you ever noticed that the paving on platform 2/3 is partly gray and partly light in color? This is no coincidence: the light-colored stones mark the presumed course of the former stage wall, which was probably as high as the top row of seats.