Today, the amphitheater still has a semi-circular seating section 70 meters in diameter, partially built on a semi-circular portico with vaulted ceilings, from where the spectators could enter the seating section through three different openings. The colorful marble flooring of the orchestra ‘pit’ is still visible; but where the stage was, one can only see holes in the floor that held the poles for the stage curtain.
Built outside of the city walls in the 2nd century AD, the entire structure was made from stone chippings mixed with lime covered in opus vittata with regularly cut blocks of grey limestone arranged in horizontal rows. The theater must have had two tiers of overlapping arches. Today you can see on both levels large sections of the external corridors.
Thanks to studies on the techniques used, the construction has been identified as a single project. In 545 AD, Totila, king of the Ostrogoths, transformed the theater into a fortress and for over a century it was used for military purposes. At the beginning of the 12th century in the amphitheater area, on about 51,000 square feet, a church was built dedicated to St Gregorio Minor, assuming that this was the place where the martyr was killed.
During the Middle Ages the theater became a market place and shops were set up in the niches under the arches.
Later, the area became a sort of quarry: the stone material was used to build the Rocca Albornoziana fortress, and later for buildings in town.
Today, most of the amphitheater, from the external corridors to the lower entrances to the seating area, have been incorporated in the city limits and is now a part of a single structure belonging to the Severo Minevio military barracks.
The structure houses Spoleto’s archeological museum, and concerts and cultural events are still held here, mainly during the well known Festival dei Due Mondi.