Sant'Andrea della Valle

Stand for a moment on the pavement and listen. Buses groan along the Corso Vittorio Emanuele, scooters weave past, and somewhere behind you water splashes into a stone basin. Then look up. A tall travertine façade rises above the traffic, pale and layered, crowded with columns, niches and statues. Climb the steps, push through the heavy door, and the noise falls away almost at once. Inside, the air is cool and smells faintly of wax and old stone. This is Sant'Andrea della Valle.

The church belongs to the Theatines, a religious order founded in the sixteenth century to reform the clergy from within. The order wanted a grand mother church in Rome, and work here began in the early 1590s. The first designs came from Giacomo della Porta and Pier Paolo Olivieri, two architects deeply involved in rebuilding the city after the Reformation. Progress was slow, and money came and went. In the early seventeenth century the project passed to Carlo Maderno, the same architect who gave Saint Peter's its long nave and its façade.

Before you go further inside, think about the façade you just passed. It was added later, in the mid seventeenth century, under the architect Carlo Rainaldi. Look again on your way out, and you will notice something odd. High up on the left, a carved angel spreads its wings to form a curving support, a scroll that links the upper storey to the lower one. On the right side... there is no angel at all. The symmetry simply stops.

Locals love to explain this gap with a story. Legend has it that the pope disliked the angel carved by the sculptor Ercole Ferrata. The offended sculptor is said to have replied that if the pope wanted another one, he could carve it himself. Nobody can prove the exchange ever happened. But the missing angel is real, and it has puzzled passers-by for more than three centuries. It is one of the small surprises of this street.

Now walk slowly up the nave. The plan is a Latin cross, a long central hall crossed by a shorter arm, with a single wide nave and chapels opening along both sides. This layout was popular with the new orders of the Counter-Reformation, the Catholic Church's response to the Protestant movement. A wide, open nave let crowds see the altar and hear the preacher clearly. Notice how few columns block your view. Your eye travels straight toward the crossing and the apse.

When you reach the crossing, stop and tilt your head back. Above you opens Maderno's dome, among the largest in Rome. Only the dome of Saint Peter's is generally ranked above it. From outside, it is one of the shapes that marks this part of the skyline. From inside, the effect is different. The dome feels less like a roof and more like an opening into a bright, crowded sky.

That sky was painted by Giovanni Lanfranco in the 1620s. His fresco shows the Glory of Paradise: rings of saints, angels and clouds swirling upward toward a blaze of light at the top. Lanfranco did not frame his figures in neat panels. He let them spill across the curve, so the painted heaven seems to continue beyond the stone. Art historians often point to this dome as one of the first great illusionistic domes of the Roman Baroque. Many later ceilings in Rome followed its example.

Now lower your gaze slightly, to the four curved triangles where the dome meets the supporting arches. These are the pendentives, and here sit the four Evangelists, painted by Domenichino. His figures are calmer, heavier and more classical than Lanfranco's swirling crowd above. The two painters were rivals, and early writers describe real tension between them. One popular tale even claims that Lanfranco tampered with Domenichino's scaffolding. Treat that as gossip, not history. The contrast in their styles, though, is right in front of you.

Domenichino also painted scenes from the life of Saint Andrew in the apse, the curved space behind the high altar. Andrew was one of the twelve apostles and the brother of Saint Peter. According to Christian tradition, he died on a cross in Greece. Lower down in the apse, large canvases by Mattia Preti show his martyrdom with dramatic light and dark. Take a moment to compare the bright fresco above with the deep shadows of the paintings below.

Here is a detail most visitors miss. High on the walls of the nave, near the crossing, sit the tombs of two popes from the Piccolomini family of Siena: Pius the Second and Pius the Third. Both men lived in the fifteenth century, long before this church existed. Their monuments first stood in the old Basilica of Saint Peter. When that ancient building was demolished to make way for the new one, the tombs were moved here. So these two older monuments now sit inside a younger church.

The ground under your feet also carries an older story. Church tradition links this area to Saint Sebastian, the early Christian martyr. According to that tradition, his body was thrown into the great drain of ancient Rome nearby before it was recovered for burial. A small earlier church once marked the spot. Just a short walk away lie the ruins of Largo di Torre Argentina and the remains of the Theatre of Pompey, buried under the later houses of this neighbourhood.

Many visitors arrive here for a different reason: opera. Giacomo Puccini set the first act of Tosca inside this church. The opera opened in Rome in 1900. In the story, the painter Cavaradossi works on a canvas in a side chapel, and the singer Tosca arrives full of jealousy. The chapel in the libretto is invented, so do not search for its name on the walls. But as you walk the side aisles, you can easily picture the scene. Some people quietly hum the music as they pass.

Before you leave, walk along the side chapels and simply look. Each one belongs to a noble family or a pious donor, and each shows its patron's taste in marble, gilding and paint. Coloured stone panels, carved family emblems and small altarpieces sit side by side. Wealthy Roman families competed for this space, because a chapel near a great preaching church brought prestige and prayers. The church is, in a way, a record of the city's powerful families.

When you are ready, step back out into the light. The noise of the Corso returns, and the fountain splashes in front of the steps. Turn around once more. Find the lonely angel on the left of the façade, then the empty space on the right. Above the rooftops, the grey dome rises against the sky. From here, Campo de' Fiori and Piazza Navona are only a few minutes on foot. As you walk away, look back now and then. The dome will follow you down the street.