Sant'Ignazio di Loyola

The draw

A dome that is not there. Andrea Pozzo painted a false dome on a canvas 13 metres in diameter at the crossing, and from one marked spot on the floor it is an entirely convincing cupola. It is the best-known optical illusion in Roman architecture and it costs nothing to stand under.

And a vault that goes further. Pozzo's Ascent of St Ignatius into Paradise runs the length of the nave, carrying the real architecture upward into painted architecture and then into sky.

It is also open until 23.30 — which means you can see it after dinner, lit, with almost nobody in it.

The friction

• The illusion only works from one place. Off the disc, the painted architecture visibly skews.
• What you are looking at is an 1823 reproduction. Pozzo's original canvas of 1685 was destroyed by fire; Francesco Manno reproduced it from Pozzo's drawings.
• Mass interrupts visiting at 18.30 daily and at 11.30 and 18.30 on Sundays and feast days.

The tactic

Find the disc before you look up. There is a marble marker set into the nave floor beneath the crossing. Stand on it, then step off it — seeing the illusion fail is more instructive than seeing it work.

Come in the evening. The church is open to 23.30, which is hours later than almost anything else in Rome, and after dark the painted sky has no real daylight competing with it.

Pair it with the Gesù. That church's façade is the model this one copies, and the two are a short walk apart — the pair shows you the Jesuit plan invented and then repeated.

Avoid 18.30 unless you are coming for the mass. Daily mass is at that hour, and 11.30 as well on Sundays and feast days.

Skip it if you:

• Cannot comfortably look straight up for a sustained period. Everything here is overhead.
• Want original Baroque paint throughout. The headline ceiling is a nineteenth-century reproduction.
• Are arriving at 18.30. You will meet a service, not a visit.

It is a working Jesuit church with a daily service. Mass is at 18.30 every day, and at 11.30 and 18.30 on Sundays and feast days; during those hours the building is not available for sightseeing.

The attraction is a painted canvas, not stone. The false dome is a canvas 13 metres across — a textile surface, already lost once to fire, hanging over an open crossing.

The viewing disc is a shared spot and a small one. The illusion only works from that one marker, so everybody wants the same square metre of floor. Take the look and move off it.

Keep the late opening worth having. A church open to 23.30 is a gift from the community that runs it, and quiet behaviour late in the evening is what keeps those hours possible.

Photograph upward, not at people. Everything worth recording here is on the ceiling, which conveniently avoids the worshippers below it.

It is free, and it is open later than almost anything else in Rome

Sant'Ignazio is an active Jesuit church, not a ticketed monument: there is no admission charge and nothing to book.

Hours

Turismo Roma publishes the opening as Monday to Sunday, 9.00 to 23.30. That is an unusually long day for a Roman church and it is the single most useful practical fact about the place.

Mass is at 18.30 from Monday to Saturday, and at 11.30 and 18.30 on Sundays and feast days. Visiting gives way to the service at those times.

Note which source says what. The parish publishes mass times and no opening hours at all; the city publishes the opening. If the two ever disagree, the parish is the one standing at the door.

Ticket & Pass Decision Matrix

One thing to know before you look up

The false dome is not Pozzo's canvas. His original, completed in 1685, was destroyed by a fire; what hangs there is Francesco Manno's reproduction of 1823, made from Pozzo's own drawings and studies.

In the evening, which almost nowhere else in Rome allows. The city publishes the opening to 23.30 daily — so this is a church you can visit after dinner, lit, with the painted sky unopposed by daylight.

Not at 18.30, unless you want the mass. That is the daily service hour, and on Sundays and feast days there is 11.30 as well.

Any season. Everything here is interior and overhead, so weather is irrelevant and winter — when the evenings start early — suits the late opening particularly well.

Midday if you want the marbles. The polychromy of the marbles and the stuccoes read best with daylight coming through the nave windows; the ceiling reads best without it. The two halves of this church want opposite hours.

Allow thirty minutes, most of it spent standing still and looking up.