The Basilica of San Martino ai Monti is located on Colle Oppio near the Colosseum

and its exact name is Basilica of Santi Silvestro and Martino ai Monti. Why did I go to visit the church of San Martino ai Monti? Because while I was looking for some exciting guided tours to participate in, I discovered that it “hides” Roman underground spaces.
NB: You can also see the basements by yourself, without booking guided tours, during the opening hours of the church. I chose to take part in a guided tour (with the Underground Rome association) because I was interested in having someone to explain to me what I was looking at.
Let’s start talking about the topic we are here for, starting from a little history of the Basilica. The undergrounds of San Martino ai Monti is the classic example of an underground space from the Roman era, and it is possible to see in a clear way the stratification of buildings that took place over time. The facade of the Basilica dates back to the 1600s, and the two Saints on it are San Martino and San Silvestro. Looking from the outside, the Basilica rests on blocks of Tufo which must have been part of Roman walls, which however were probably moved from their original place. Over the centuries the city has undergone many changes, and around 1200 the undergrounds ended up “covered”, to be discovered for the first time in the 1600s. Only in 1900, however, were they definitively brought to light (after yet another rediscovery). Before going down to the basement, we pause for a moment inside the Basilica. The cycle of frescoes by Nicola Douget is fascinating: 18 episodes in the history of the prophet Elijah who, contrary to what happened at the time, focus mainly on landscapes. The columns date back to the 9th century, to the “beginnings” of the history of San Martino ai Monti; we note that they were raised because with the various changes undergone by the church they were no longer sufficiently high.
The basements of San Martino ai Monti date back to the third century and could have been born as service areas of the thermal baths of Traiano, which were always located on Colle Oppio. To access the basement, you pass through the crypt, dating back to around 1600. What you can see the remains of was perhaps a titulo, or an ante litteram “parish”, dating back to Roman times when Christianity was not yet legal (therefore it was not can pray openly). To overcome the problem of illegality, the faithful met in private homes, identified by the titles with the name. Subsequently, the first official parishes were built over these tituli. This place was the house of Equizio, on which Pope Silvestro founds this titulo. According to some documents, the tituli were two: that of Equizio and that of Silvestro, but it isn’t clear what the real situation was.
From the III century, the time of construction of the building, only one decoration arrived at us: given the (low) quality of the decorations, it seems that perhaps it was not a private house, but a public environment where the Christian faithful could go to pray. We can also note that some parts are much more recent: in 1930 some structures collapsed and were then rebuilt. Personally, meanwhile, taking part in this visit has allowed me to see aspects of Rome that I did not know, even though I was born and raised here: with each visit, with each discovery I am becoming more and more curious to discover and understand something more than my city.