Underground Rome: San Clemente basilica church

Walk through the “layers” of Rome!

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The Church Basilica of San Clemente in Rome is a real lasagna of history, which is about 400 meters from the Colosseum.

Do you understand what I mean when I say Rome is like a “lasagna of history”? If you are still not sure, then keep reading. Because you are about to go underground Rome and learn all about this super “lasagna of history”!

This church is dedicated to Saint Clement, the third pope after Saint Peter! When you visit this church, you’ll end up exploring three levels. Each of them is very different and belongs to a different era from the other. It’s like a proper lasagna of history! 😜

To be exact:

  • Modern street level: basilica built in the XII century
  • Level -1: basilica built in the IV century
  • Level -2: ancient Roman ruins

But now let’s start exploring this incredible place, from the top to the underground!

The overground layer: the medieval basilica church of San Clemente

The first layer we’ll get to explore is the upper one, the only layer which is overground: the “modern” basilica.

When I say “modern” I mean the newest layers of all three, but this basilica dates back to the XII century! It was in fact completed in 1123.

It is therefore a medieval basilica

As we enter the gate of the basilica of San Clemente we walk through a beautiful cloister. Then we enter the main door and.. wow! 🤩

This basilica inside is incredibly beautiful. Wooden ceiling, cosmati floors, ancient columns and the mosaics! It has all the features of a typical medieval church, which are:

  • Cosmati floors: floors made of tiny fragments of colourful marbles, usually in a pattern with big circles and small squares. The “Cosmati” name comes from a Roman medieval family which was specialized in producing these kinds of floors
  • Wooden ceiling
  • Mosaics in the apse (the semi-dome on top of the altar). This represents the tree of life which starts its journey towards the passion of Christ. Christ is on the cross between Mary and Saint John
  • Many different ancient columns on the sides of the central nave. These columns are usually all different from each other because they come from ancient Roman buildings. The ancient Roman ruins were very often stripped of their materials, which were then reutilized to make churches and other buildings

In the center of the nave you can see the Schola Cantorum, which was where the choir was singing during the mass.

Once we filled our eyes with the beauty on the upper layer, let’s walk towards the sacristy. This is where we can access the underground area of San Clemente!

Walking towards the underground level of San Clemente

san clemente church rome
The entrance to the sacristy

The sacristy is where you get your tickets to the archaeological area and start walking the stairs down.

Here you will find the ancient basilica of San Clemente, built in the 4th century! This basilica is right below the modern one and in the middle ages it used to be one of the most important basilicas of Rome.

underground rome basilica church san clemente
The ancient basilica of SanClemente built in the 4th century

Why building a new basilica on top of the old one?

This old basilica was unfortunately severely damaged during the Sack of Rome in 1084 by the Normans. After the Sack the basilica was abandoned and then filled with ground to build the new basilica on top of it.

One of the first written swear words in history! 😅

When you are in the central nave of this ancient basilica, and have the altar in front of you, look to the left.

underground rome Saint Clement basilica church
On the left, the fresco with the swearword 😊 On the right, the altar of the 4th century basilica

You will see remains of the beautiful frescoes that once decorated the church. But there is one in particular which you should really notice! Look for the first fresco before the altar.

In the lower section of this fresco you will see a sort of “comic”, characters with written words next to them.

Starting from the right, we have a character whose name is Sisinnio, which is giving orders to his slaves, on the left of the scene. Sisinnio ordered his slaves to bring him Saint Clement, who was imprisoned. Saint Clement in the meantime freed himself, and when the slaves go and pick him up from the jail they mistakenly take a column

They complain about the weight of Clement, without realizing they are not actually carrying him 😅

In the meantime Sisinnio, on the right of the scene he says: “fili de puta, traite!”, which translates to “sons of xxxxx, keep pulling!” 😅

This is written in vulgar language, the precursor of modern Italian. And this is the very first written swear word in vulgar language in history! 

underground rome Saint Clement basilica
Can you read “fili de le pute, traite”?

Moving on to the next room..

As you enter the following room, on the right you will find an altar with lots of inscriptions and a mosaic of Saint Cyril, a missionary from Thessalonica in the Byzantine empire, in today’s Greece.

underground rome Saint Clement basilica Saint Cyril altar
The altar of St Cyril underground Saint Clement basilica

Why Saint Cyril in the basilica of San Clemente?

Here is a short version of the story.

Cyril set together with his brother Methodius in the IX century (800s), to evangelize the Slavs. They created the Glagolitic alphabet, the first alphabet to write the Slavic language, which was the language understood by most of the population. Thanks to this alphabet the brothers were able to translate the Christian Sacred texts and make them accessible to the Slavs.

The Cyrillic alphabet was created later (not by Saint Cyril) taking inspiration from the Glagolitic alphabet.

And now the connection with Saint Clement.

During a mission in Crimea, Saint Cyril found the relics of Saint Clement. The Pope asked Cyril and his brother Methodius to bring these relics to Rome. The brothers came to Rome and the relics were buried here, in the basilica of San Clemente.

Unfortunately shortly after Cyril died, and Methodius wanted to bring his brother’s body back home to Greece. But the Pope and the Romans were so sad about it, that Methodius decided to leave his brother in Rome. Therefore Saint Cyril was buried here, in the basilica of San Clemente.

Let’s continue our journey through the layers..

The third and lowest level underground

From the Saint Cyril altar we’ll take the stairs and move down to the third and lowest level!

In here we will find ruins of ancient Roman private and public buildings, separated by an alley (which today is of course covered).

The private building was later turned into a Mithraeum (in the 3rd century).

The Mithraeum from the 4th century

What is a Mithraeum?

The Mithraeum was the “temple” of the Mithraic mystery cult, which was a cult as popular as Christianism in the middle ages. This cult celebrated the God Mithra and the ceremonies were taking place in these small temples, the Mithraeums. 
Mithraism was a mystery cult that could only be practiced by men and the rituals were only revealed to the initiates. The fact that it was not an inclusive religion like the rival Christianism, contributed in the Mithraism to decline and disappear in the 5th century

If we keep walking through this underground area we will find other rooms from ancient Rome. One of these buildings is believed to be the Ancient Roman Mint built by the emperor Domitian, the so-called “Moneta” (this is where the word “money” comes from!).

You will also notice that these walls had no windows and had very thick walls, to protect the coins inside.

As you explore the various rooms, you will hear at some point the sound of the water. That is the Labican stream, which was used to cool down the coins that were just minted!

How incredible has this journey to the center of the earth been? 🤩

The Basilica of San Clemente really gives you a clear picture of how Rome always stood up (literally!) from its ashes and reborn on top its own ruins!

A true “lasagna of history”! 😊

How to visit the Basilica of San Clemente

To visit the basilica you need to purchase a ticket, which can be booked here: https://eu5.bookingkit.de/onPage/detail?cw=2d051ec3a783322fa6ab60eb31a79680&preview=1&e=88bbbeb9cb335dd9125e32d96e80b3d9

I hope this article will be useful as a “guide” on your visit to the San Clemente basilica! 😊

Save it for later and let me know in the comments how was your visit or if you are planning to go! 😊

Written by Federica

Creative director of Live Virtual Guide. Her favorite things are gelato, pizza and the hidden gems of Rome.

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  1. Jennifer

    This is such a great overview about San Clemente! You made it so easy.. Thanks so much for sharing!

    • Federica

      Thank you Jennifer! I am so happy to read that! 😊

  2. Sam

    I wish I read this earlier, before I visited San Clement! Thank you so much

    • Federica

      Sounds like a good reason to come back to Rome! 😉

  3. Ronald Yarrosh

    Great summary.
    I actually count this as a four layer lasagna. The fourth layer is the façade and ceiling by Carlo Fontana completed in 1719. If you want a fifth layer, you could add the electric lights. Such a worthwhile introduction to what you will see in the rest of Rome.

    • Federica

      You are right Ronald! If we look at all the details we will never end counting the layers, there are so many! 😊 And as you say, it does sum up what Rome is!

  4. Lawrence

    I missed this place the last time I went to Rome. This will be on my bucket list for my next Italian adventure. Thanks for sharing Frederica.

  5. Eileen Panetta

    I have visited San Clemente twice when in Rome but was never quite sure what I was looking at. Your tour made it very clear. I can’t wait to visit again. Thank you!

    • Federica

      Thank you Eileen, I am happy this will help understand this super lasagna of history! 😊

  6. Katerina

    Saints Cyril (Constantine) and Methodius were neither Greeks nor Bulgarians. They were Slavs from Macedonia. True, they were the sons of a Byzantine official from Salonika, they were educated at the Magnaur Academy in the imperial court of Byzantium and Cyril was chief of the patriarchal library in Constantinople.

  7. Judy

    Fantastic – I wish I knew about this before visiting Rome. Yet another reason to return!


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