Santi Giovanni e Paolo al Celio

Listen first. The traffic of the Colosseum is only a few minutes' walk away, but up here it fades to a low hum. Your feet are on old stones, uneven and worn smooth. A bell tower rises above a quiet square, and arches cross the narrow lane overhead. You are on the Caelian Hill, one of the seven hills of ancient Rome. In front of you stands the Basilica of Saints John and Paul, a church built on top of a story many layers deep.

Start with the name. According to Christian tradition, John and Paul were two brothers who served at the imperial court in the fourth century. The story says they refused to give up their faith under Emperor Julian, the ruler who tried to restore the old Roman gods. Tradition holds that they were executed in secret, inside their own house, and buried there. Historians treat the details with caution. But the belief that the martyrs lived on this spot shaped everything you see today.

The church itself goes back to the late fourth century. Its founder was a Roman senator named Pammachius, a wealthy Christian and a friend of the scholar Saint Jerome. Early churches in Rome often began as private houses where believers met. They carried the name of the owner, and this one was known for a time as the church of Pammachius. Later, the dedication to the two martyrs took over, and the old name slowly faded away.

Now turn your attention to the lane that runs along the left side of the church. This is the Clivo di Scauro, an ancient street that still follows its Roman line. Look up. Heavy brick arches span the street, connecting the church wall to the buildings opposite. They were added in the Middle Ages as buttresses, to stop the walls from leaning outward. Walking beneath them feels like passing through a series of stone gateways... and it is one of the quietest walks in central Rome.

Here is the first surprise. Along that same lane, if you look closely at the side wall of the church, you can see traces of an older building. Blocked windows, doorways, and courses of Roman brick show through the later masonry. That is because the church was built directly over Roman houses. The builders did not tear them down. They filled them in and used them as a foundation. The ancient homes are still there, sealed underneath your feet.

Those houses were rediscovered in the late nineteenth century by a priest of the Passionist order, which still cares for the church today. He was searching for the tomb of the martyrs. Instead, he found rooms with painted walls, staircases, and a small chapel-like space with Christian images. Today this underground complex is known as the Case Romane del Celio, the Roman Houses of the Caelian. It is entered from the Clivo di Scauro, and it requires a separate visit.

Inside those houses, the frescoes are the real reward. Some show pagan scenes: figures, birds, plants, and garden motifs in soft reds and greens. Others carry early Christian imagery. Seeing both in one place shows how Roman homes changed as the city slowly became Christian. It is rare to stand inside an ordinary Roman house this complete. Most of what survives in Rome is temples, baths, and palaces. Here, you see where people actually lived.

Back in the square, look at the bell tower. It dates from the twelfth century, and it is a fine example of Romanesque style — the rounded arches and stacked levels of medieval church building. Now the second surprise. The tower stands on the massive stone foundations of the Temple of the Divine Claudius, built to honour the emperor after his death. The base blocks are ancient Roman work. The medieval brick sits on top, like a new house built on an old cellar.

Look higher up the tower. Set into the brickwork are round glazed ceramic bowls, decorations that medieval builders liked to add. The ones you see today are copies. The originals were removed for protection and are kept elsewhere. On a bright afternoon, the glaze still catches the light. It is a small touch of colour on a tower otherwise made of brown brick and travertine, the pale local limestone used across Rome.

The front of the church also comes from the Middle Ages. A portico of ancient columns runs across the façade, with a gallery above. The columns were taken from older Roman buildings, which was common practice. Walk around toward the back, and you may glimpse the curved apse, the rounded end of the church. Its upper part has a small open gallery of arches. This kind of gallery is typical of northern Italy, and it is very unusual in Rome.

Step inside, and the mood changes completely. The medieval shell was remodelled in the early eighteenth century, so the interior feels light, formal, and Baroque. Pillars line the nave, and the ceiling is painted and gilded. Above all, look at the chandeliers. Rows of crystal chandeliers hang down the length of the church. When they are lit, the whole space glitters. This is one reason the basilica is one of the most popular wedding churches in Rome.

In the floor of the nave, look for a small area enclosed by a railing. This marks the spot traditionally linked to the martyrdom of John and Paul. It connects the bright church above with the dark rooms below. Off to one side is a large chapel dedicated to Saint Paul of the Cross, the founder of the Passionist order. His body rests here. The monks still live in the monastery next door, and their quiet presence is part of the place.

Before you leave, stand for a moment back in the square. Notice the tall trees of the Villa Celimontana park nearby, the soft colour of the brick, the sound of footsteps on the lane. Above ground is a medieval tower on a Roman temple. Inside is a Baroque church. Below is a Roman home. As you walk down the Clivo di Scauro under those old arches, remember that every step passes over one more layer of this city.