The burial area beneath the villa of Prince Torlonia was discovered in Nov. 1919 during building work. A brief report was published by Marucchi (1920), and Paribeni (1920) studied some of the inscriptions. Frey visited three times in 1928 and Leon made several visits, the latest in 1951. Beyer & Lietzmann (1930) gave a full account of the site and inscriptions, and a detailed plan. The Villa Torlonia became a residence of Mussolini, and the catacombs sustained some damage during World War II. Emergency repairs were carried out by the Commissione di Archeologia Sacra in 1946 (Leon (1960), p.63). A three-year restoration programme led to Fasola's publication (1976) of a new plan and many new inscriptions, but this was too late for inclusion in CIJ i. No measurements or facsimiles have ever been published for most of the scratched and painted inscriptions. Unfortunately, further restoration work being carried out in 1994 by the Sovrintendenza di Archeologia prevented me from visiting the catacombs and seeing the inscriptions which are still there.

It became apparent to Beyer & Lietzmann that there were really two separate catacombs here, with independent entrances, which had run into each other in antiquity. They joined at the crossing of Gall.E1 of the lower catacomb and C1 of the upper. A staircase has now been installed to allow access between the two. The catacombs lie near the Via Nomentana, but were only accessible from a side road near the modern Via Lazarro Spallanzani (Fasola, p.61).