Rome in Layers: The Quiet Celian Hill, San Clemente & the Lateran

Down through three churches stacked on a pagan temple, past round martyr halls, nuns behind a turning wheel and a hand-crushing obelisk, to the mother church of Rome

Rome · 11 stops · 26 min audio · Generated October 2026

1. 1. San Gregorio al Celio: The Monastery That Converted England

   Piazza di San Gregorio 1, 00184 Roma RM, Italy

   Climb the wide flight of steps and stop in front of the pale baroque facade, with the traffic of Via di San Gregorio humming behind you. It looks like one more grand Roman church. But if you happen to be English, or speak English, this is quietly one of the most important doorways in your history.

   In the sixth century, this hillside belonged to a rich Roman family. Their son, Gregory, had been prefect of the city, the highest civil office in Rome. Around 575 he gave it all up, turned the family house into a monastery dedicated to Saint Andrew, and became a monk. A few years later, very much against his wishes, he was made pope. History calls him Gregory the Great.

   The story told by the English monk Bede goes like this. Walking through the market one day, Gregory saw fair-haired boys for sale as slaves. He asked who they were. Angles, he was told. Not Angles, he replied, but angels... Whether or not he ever said it, in 596 he sent the prior of this very monastery, a monk called Augustine, north with a party of around forty brothers. They landed in Kent, baptised its king, and Augustine became the first Archbishop of Canterbury.

   So the line of archbishops that still leads the Church of England begins with a man who walked out of this door. That is why archbishops of Canterbury keep coming back. In 2016 Pope Francis and Archbishop Justin Welby prayed vespers together in this church, using Gregory's own story as their meeting point. Beside the church stand three small chapels. In one, frescoes by Domenichino and Guido Reni face each other across the room, two rivals painting the same saint's martyrdom side by side.

   In another, the chapel of Saint Barbara, there is an ancient marble table where Gregory is said to have fed twelve poor men every day. Legend says that one day a thirteenth guest sat down, and Gregory realised he had served an angel. Now walk to the steep, narrow lane that climbs beside the church, the Clivo di Scauro, and go up under its arches. You are about to walk on an ancient Roman street.

2. 2. Santi Giovanni e Paolo & the Roman Houses Beneath

   Piazza dei Santi Giovanni e Paolo 13, 00184 Roma RM, Italy

   Walk slowly up the Clivo di Scauro and notice the brick arches flying over your head from one side of the lane to the other. They are buttresses, propping up the side wall of the church on your left. And the cobbles under your feet follow the line of the Clivus Scauri, a street that has been climbing this hill for two thousand years.

   The church at the top is dedicated to Saints John and Paul. Not the apostles... two Roman officials. According to their legend, they were executed in the 360s under Julian the Apostate, the last pagan emperor, and buried secretly in their own house. Before the end of the fourth century, a senator called Pammachius built a church directly on top of that house.

   For centuries this was a pious tradition. Then, in 1887, a Passionist priest called Father Germano started digging under the floor. He found the houses. Not one room but more than twenty, a whole block of Roman homes and shops, built between the second and fourth centuries. On the walls, painted young men hold garlands among birds and vines, cupids fish from little boats on a painted sea, and in one small shrine on the stairs, a later painting shows martyrs kneeling before execution. The Case Romane del Celio, as they are called, have been open to visitors since 2002, and the entrance is right here in the lane.

   Now look up at the bell tower. It is twelfth-century Romanesque, decorated with glazed ceramic bowls, and it stands on enormous blocks of travertine. Those blocks belonged to the Temple of the Divine Claudius, the emperor deified after his death, whose huge platform covered much of this part of the hill.

   Inside the church lies Saint Paul of the Cross, who founded the Passionist order and died here in 1775. His brothers still live in the monastery next door. Martyrs in the cellar, a temple under the tower, a saint in the chapel: three layers of Rome in one square. Now follow Via di San Paolo della Croce along the monastery wall, towards an old arch with an aqueduct running over its top.

3. 3. Arch of Dolabella & the Little Boat of the Navicella

   Via di San Paolo della Croce, 00184 Roma RM, Italy

   Stand in front of the plain travertine arch at the top of the lane and read the faded letters cut across it. They name two consuls, Publius Cornelius Dolabella and Gaius Junius Silanus, and they date the arch to the year 10, when Augustus was still alive. Above it, a line of brick arches marches off into the distance.

   Those brick arches are the Arcus Neroniani, a branch of the Claudian aqueduct extended by Nero to bring water across the Celian Hill. His engineers simply used the old arch as a ready-made support and ran the water over the top. Rome rarely knocks anything down when it can build on it instead.

   Now look to the right of the arch, above a small gateway. There is a round mosaic, made around 1210 by a father and son of the Cosmati family of marble workers. Christ sits enthroned, holding the wrists of two chained men, one black and one white, and he is setting them free. It was the emblem of the Trinitarian order, founded to ransom Christian captives from slavery. Their founder, Saint John of Matha, died in 1213, and tradition says his cell was built into the top of this very arch.

   Walk a few steps on to the little square in front of the church of Santa Maria in Domnica, and you will find a marble boat sitting in a fountain. This is the Navicella, the little ship. It is a sixteenth-century copy, made for Pope Leo the Tenth, of an ancient votive boat found nearby, perhaps an offering left by soldiers from a Roman barracks that stood on this spot. Romans have called the church Our Lady of the little boat ever since.

   Step inside if the door is open. In the apse, a ninth-century mosaic shows Pope Paschal the First kneeling at the feet of the Virgin, with a square halo behind his head. The square means he was still alive when it was made. Now go in through the gate of Villa Celimontana, right beside the church, and follow the main path into the gardens.

4. 4. Villa Celimontana & the Obelisk That Kept a Man's Hands

   Via della Navicella 12, 00184 Roma RM, Italy

   Follow the gravel path under the umbrella pines until you reach a slender obelisk standing in the middle of a lawn, surrounded by benches and the shouts of children. It looks almost modest by Roman standards. Which is exactly why almost nobody stops to ask where it came from.

   In 1553 a nobleman called Ciriaco Mattei bought a vineyard on this hill and turned it into one of the great gardens of Renaissance Rome, filled with fountains, ancient statues and fragments of carved marble. Every collector of the age wanted one thing above all: an Egyptian obelisk. In 1582 the city council gave him one, a small obelisk that had stood near the church of Aracoeli on the Capitoline Hill.

   Only the upper part is the genuine ancient Egyptian original, carved with the name of the pharaoh Ramesses the Second. It almost certainly reached Rome to decorate the great temple of Isis on the Campus Martius. The rest of the shaft was added to make it tall enough for a nobleman's pride. So you are looking at three thousand years of history stacked on a Renaissance afterthought.

   And then there is the story the gardeners like to tell. When the obelisk was moved to its present position in the early nineteenth century, the stone slipped as it was lowered onto its base, and it crushed the hands of one of the workmen. They could not lift it again. The story goes that his hands are still down there, under the obelisk, to this day.

   The villa later passed through several owners, and in 1925 the state bought it. A few years later it became a public park. On summer nights, a jazz festival fills these lawns with music, and the Italian Geographical Society works in the villa's palazzina. Leave by the gate on Piazza della Navicella and cross into Via di Santo Stefano Rotondo. Look for a low round building behind a garden wall.

5. 5. Santo Stefano Rotondo: The Round Church of Martyrs

   Via di Santo Stefano Rotondo 7, 00184 Roma RM, Italy

   Walk through the gate and into the garden, and see the low, round brick building sitting in the grass like a giant drum. Then step inside, and let your eyes adjust. You are standing in a circle of ancient columns, under a ring of light, in one of the oldest round churches in the world.

   Santo Stefano Rotondo was consecrated under Pope Simplicius, around 470. Nobody built churches like this in Rome. The original plan had three rings inside one another, more than sixty metres across, and many scholars think it was inspired by the round rotunda over the tomb of Christ in Jerusalem. It was dedicated to Stephen, the first Christian martyr, and it was built as a monument, not a parish.

   Now look at the outer wall. All the way round run thirty-four painted scenes of martyrdom, from the late sixteenth century, by Niccolò Circignani and Antonio Tempesta. Saints are boiled, flayed, crushed, burned and torn apart, each scene labelled with the emperor responsible. The church belonged to the Jesuits' German and Hungarian college, and the frescoes were a lesson for young priests about to be sent into the religious wars of northern Europe: this could happen to you.

   Charles Dickens visited in the 1840s and wrote that he could not imagine a more horrible panorama of butchery even in his dreams. He was not wrong. Look for a small chapel with a seventh-century mosaic, too. Two saints stand on either side of a jewelled cross, with the head of Christ at the top, a quiet golden image in the middle of all that blood.

   And under the floor... another layer. In 1973, excavations beneath the church found a Mithraeum, a cave-like temple of the soldiers' god Mithras, belonging to a Roman barracks that stood here. A pagan sanctuary under a martyrs' church. Hold on to that idea. Head north now, down the hill through the backstreets towards Via Labicana, where a whole church is buried under another.

6. 6. San Clemente: Three Churches Deep

   Via Labicana 95, 00184 Roma RM, Italy

   Step into the basilica and let your eyes go straight to the apse. A golden mosaic glows there, a cross growing out of an enormous acanthus plant whose curling tendrils fill the whole vault with birds, deer, peasants and little scenes of daily life. It was made in the twelfth century, and it is one of the most beautiful mosaics in Rome. But the real wonder of San Clemente is under your feet.

   In 1857 the Irish Dominican prior, Father Joseph Mullooly, whose order has looked after the church since 1667, began to dig beneath the floor. He found a whole church. The basilica you are standing in was built in the early 1100s on top of an older one, from the fourth century, which had been filled with rubble after Norman troops sacked this area in 1084. Walk down the stairs and you are in it.

   Down there, on the walls of that older church, there is an eleventh-century fresco that is famous for its dialogue. A pagan called Sisinnius orders his servants to drag away Saint Clement, but a miracle has turned the saint into a stone column. Painted beside the servants are the words Sisinnius shouts at them, among the earliest written lines of Italian, and they are not polite. Roughly: pull, you sons of whores. Italian literature begins with a swear word in a church.

   Go down one more staircase and the air gets cooler. Now you are in the first and second centuries, among the streets and rooms of Roman buildings raised after the Great Fire of 64. In one of them, a low vaulted room with stone benches, is a temple to Mithras, the god of soldiers, with an altar showing him slaying a bull.

   And listen. Somewhere in the dark you will hear water running fast, an underground stream still flowing through ancient channels, heading, they say, for the great Roman sewer. Three churches deep, two thousand years down, and the water does not care. Come back up into the daylight, and climb the steep Via dei Querceti to the fortress-like walls at the top.

7. 7. Santi Quattro Coronati: The Nuns' Wheel & the Emperor's Bargain

   Via dei Santi Quattro 20, 00184 Roma RM, Italy

   Pass under the squat bell tower into the first courtyard, then into a second, and you will feel the noise of the city fall away behind you. With its high walls and narrow gate, this place looks less like a church than a castle... and for a time in the Middle Ages, that is exactly what it was.

   The Four Crowned Martyrs who give the church its name were, according to tradition, stonecutters and soldiers killed for refusing to carve or worship a pagan idol. That is why for centuries Rome's stonemasons and sculptors claimed them as patrons. The church was rebuilt in the early twelfth century after the Norman sack of 1084, smaller than before, which is why the courtyards feel oddly vast for the building.

   Today it is home to a community of enclosed Augustinian nuns. If you want to see its greatest treasure, find the door to the oratory in the courtyard, ring the bell, and speak to a wooden wheel set into the wall. A voice you will never see answers you, the wheel turns, and a key appears. That key opens the Oratory of San Silvestro.

   Inside, the walls are covered with frescoes painted in 1246, as fresh as comics. They tell a legend. The emperor Constantine is sick with leprosy; Saints Peter and Paul appear to him in a dream; Pope Sylvester baptises and cures him. Then, in the final scenes, the grateful emperor hands the pope his tiara and leads the pope's horse on foot, like a groom.

   That was no innocent picture. It was painted at the height of the war between the papacy and the emperor Frederick the Second, and its message was blunt: emperors serve popes. Painted propaganda, behind a nuns' wheel. Before you leave, ask whether the cloister is open, one of the oldest in Rome, with a fountain in the middle. Then walk east along Via dei Santi Quattro. Before long, the tallest obelisk in the world will appear ahead of you.

8. 8. The Lateran Obelisk & the Baptistery of Constantine

   Piazza di San Giovanni in Laterano, 00184 Roma RM, Italy

   Stand in the square and tip your head back as far as it will go. The red granite needle in front of you is the tallest ancient Egyptian obelisk still standing anywhere on earth, over thirty metres of stone before you even count the pedestal. It is around three and a half thousand years old.

   It was raised at Karnak, in Thebes, for the pharaoh Thutmose the Third, and finished by his grandson. Constantine wanted it for his new city on the Bosphorus, but it was his son, Constantius the Second, who finally shipped it to Rome in 357 and set it up in the middle of the Circus Maximus. When the empire fell, it toppled and broke into three pieces and vanished into the mud. In 1587 it was dug up, and the next year Domenico Fontana repaired it and raised it here for Pope Sixtus the Fifth, crowned with a cross.

   Now turn to the low, eight-sided brick building beside the basilica. This is the Lateran Baptistery. Constantine built the first one here, and in the fifth century Pope Sixtus the Third rebuilt it with this octagonal plan. Eight sides, for the eighth day, the day of resurrection. From here the shape spread across the Christian world, to Ravenna, Florence and far beyond.

   Medieval Romans believed that Constantine himself had been baptised in this font. He was not. He was baptised on his deathbed, far away near Constantinople, in 337. But a good legend is hard to kill. Inside, ask to see the bronze doors of the chapel of Saint John the Baptist. The story goes that if you open them slowly, the old metal hinges sing, a long low note like an organ.

   Every Easter for centuries, adult converts walked down into the font here and came up as Christians. This octagon is where Rome's Christianity was, quite literally, born again. Now cross the square to the long white building on its far side, with one door and many people waiting in front of it.

9. 9. The Scala Santa: Twenty-Eight Steps on Your Knees

   Piazza di San Giovanni in Laterano 14, 00185 Roma RM, Italy

   Go in through the central door and you will see a wide staircase rising ahead of you, and people climbing it very, very slowly. Nobody is walking. Every single person is on their knees, one step at a time, murmuring prayers.

   These are the Scala Santa, the Holy Stairs. Tradition says they are the twenty-eight marble steps of Pontius Pilate's palace in Jerusalem, the steps Jesus climbed on the day of his trial, and that the emperor Constantine's mother, Helena, brought them to Rome in the fourth century. For more than a thousand years they belonged to the old Lateran palace where the popes lived. When Sixtus the Fifth rebuilt the whole area, Domenico Fontana moved them into this building, finished in 1589.

   For most of the last three centuries you could not even see the marble. The stairs were cased in walnut wood to protect them from millions of knees. In 2019, after restoration, the wood was removed for about two months, and pilgrims climbed on the bare stone for the first time in almost three hundred years. Look closely at the wooden covering, and you will see small windows where tradition marks drops of Christ's blood.

   One pilgrim who climbed them was a young Augustinian monk from Germany, around 1510. His name was Martin Luther. His son later reported that, as he prayed his way up, step after step, he was struck by a question he could not shake off: who knows whether it is true? A few years later he published his ninety-five theses, and Europe split in two.

   At the top is the Sancta Sanctorum, the Holy of Holies, once the private chapel of the popes, glittering with thirteenth-century frescoes and mosaics. Its most precious treasure is an ancient icon of Christ said to be not made by human hands. If you do not want to climb on your knees, side staircases let you walk up normally. When you come out, turn left and walk to the gigantic facade crowded with statues across the square.

10. 10. San Giovanni in Laterano: The Mother of All Churches

    Piazza di San Giovanni in Laterano 4, 00184 Roma RM, Italy

    Stand back far enough to take in the whole facade, a vast wall of white travertine topped by fifteen colossal statues, Christ in the centre and the saints on either side, each one about seven metres tall. Under them, the Latin inscription makes an enormous claim: this is the mother and head of all the churches of the city and of the world.

    Most visitors assume that the pope's cathedral is Saint Peter's. It is not. It is this one. San Giovanni in Laterano is the cathedral of Rome, the seat of its bishop, and it was the first great church Constantine ever built, dedicated around 324. For about a thousand years the popes lived right next door, until they left for Avignon in the fourteenth century.

    Now the layer underneath. Before 312, this ground was the barracks of the emperor Maxentius's mounted bodyguard. That year Constantine beat Maxentius at the Milvian Bridge, and the horse guards fought on the losing side. Constantine disbanded them, razed their barracks, and built his church on top. So the mother of all churches stands, quite literally, on the ruins of a defeated army.

    Go inside and look at the great bronze doors of the central entrance. They are ancient Roman doors that once closed the Senate House in the Forum, moved here in the seventeenth century. The nave beyond is the work of Francesco Borromini, who remodelled it for the Jubilee of 1650, wrapping the old columns in huge piers with niches for giant apostles. And in the Lateran palace next door, in 1929, Mussolini and the Holy See signed the treaty that created Vatican City.

    A church built by an emperor, on a ruined barracks, with the doors of the Senate and the walls of a baroque genius. Layers again. Every year on the ninth of November, the whole Catholic world celebrates the dedication of this building, a birthday party for a church. For the final stop, turn your back on the facade and cross towards the old city walls. Just to the left of the modern gate, an older one sits sunk deep below the road.

11. 11. Porta Asinaria: The Gate Where Rome Was Betrayed

    Piazza di Porta San Giovanni, 00183 Roma RM, Italy

    Walk along the old brick wall until you reach a gate flanked by two massive round towers, and look down. The gate is sunk metres below the modern road, as if the city had slowly risen around it like a tide... which is exactly what happened.

    This is the Porta Asinaria, one of the gates of the Aurelian Walls, built in the 270s when Rome, for the first time in centuries, felt it needed protecting. The two towers were added a little later, when the walls were strengthened against the barbarian invasions. Nobody is quite sure where the name comes from: perhaps a family called the Asinii, perhaps a road. Romans, naturally, have always preferred to think it was the donkeys' gate.

    In the winter of 546, Rome was besieged by the Gothic king Totila. The city was starving. According to the historian Procopius, a few of the soldiers guarding this gate, Isaurians from Asia Minor, made a secret deal with the enemy. One night they opened the Porta Asinaria from inside, and the Goths poured in. The city that had once ruled the world was taken through a side door, by a bribe.

    By then the population had collapsed, and in the years that followed, Rome would shrink to a few tens of thousands of people huddled near the river. Over the centuries rubble, earth and new streets raised the ground around the gate, until in 1574 Pope Gregory the Thirteenth closed it and opened the new Porta San Giovanni right beside it, the one the traffic still uses.

    And that is the whole walk in one picture. You began at a monastery that sent monks to the end of the known world, went down into a church buried under a church, past martyrs, nuns and a pharaoh's needle. Every step was a layer laid on top of another, and here the oldest layer is still visible, waiting at the bottom. San Giovanni metro station is just outside the gate, if your legs have had enough of time travel.