The neopythagorean basilica at Porta Maggiore is one of Rome’s hidden treasures. The secret gathering place of a mysterious eastern cult, it was sealed and destined for oblivion as early as the first century AD. With three naves, the basilica is entirely covered with refined white stucco decorations. The building is some 12 meters below ground, beneath the tracks leading into Rome’s central train station. In fact, it was during work on the tracks that a heavy excavator broke through into the bowels of the earth and revealed the underground monument. Unfortunately, the exposure also disrupted the centuries-old environmental stability that had enabled the building to survive intact for so long.
The new conditions of thermo-hygrometric instability, combined with sources of atmospheric and biological pollution and vibrations from passing trains, led to a serious state of decay for the building and its stucco decorations. The CCA, Centro di Conservazione Archeologica, was asked to devise a conservation project, which entailed large-scale work and many technical challenges. Cleaning, consolidating and protecting the decorations were some of the treatments carried out during the two years of the program. Biological treatments and preventive conservation measures rounded out the technical operations.