That's Italian: view of St. Peter's Basilica from Via della Conciliazione
Marla Holden/Alamy

Centuries collide in Rome, a city where change is constant — but always beautiful.

ON A SERENE SUNDAY AFTERNOON IN ROME, my fiancée and I settled into lunch in a piazza. We had spent the morning attending Mass at St. Peter’s Basilica, and we needed a quiet place to absorb all the grandeur of that ritual. So we headed across the Tiber River from Vatican City to the open rectangle of Campo de’ Fiori. Sunday being a day for family rather than business in Rome, the produce stalls and souvenir stands in the Campo were smaller and slower than usual, and agreeably so.

Searching for the kind of restaurant that feeds the locals, we turned down a side street from Campo de’ Fiori into the cobblestoned Piazza del Biscione. Spotting several extended families tucking into pranzo della domenica, the Sunday midday meal, we took a table for ourselves at Ristorante da Pancrazio. Over plates of comfort food rendered with loving finesse — ravioli with artichokes, spaghetti with black pepper and pecorino, fresh asparagus, house wine — we joyfully debriefed on the day thus far.

As we got up to leave, the waiter motioned insistently toward a staircase. His gesture baffled me because just 10 minutes earlier, when I’d started in that direction looking for the men’s room, I had been redirected. So why all the urgency to check out the basement now?

The steps led, it turned out, to the remains of Teatro di Pompeo, Pompey’s Theatre. Entire columns stood intact, whole rooms with barrel ceilings and wall murals. In its era, the theater had seated close to 40,000 spectators. It also included a curia, an assembly place where Roman senators often met for discussions. It was here that, on the Ides of March in 44 B.C., Julius Caesar was stabbed to death. What kind of gratuity, I had to wonder, does one leave a waiter for this kind of recommendation?

In that moment of stepping down so effortlessly from the epicurean present to the epic past, I felt all my ­responses to Rome suddenly jell. This city, to use the jargon of our day, is the great mash-up. It is the place where Roman Empire, Catholic Church, pagan, Christian, Jew, modern nationalism, La Dolce Vita indulgence and penitential sacrifice co-mingle, one street to the next, one layer above or below. In Rome, more so perhaps than anywhere on Earth, each era cannibalizes its predecessor, yet always in a way that leaves evidence behind, so that the lineaments can be observed and admired.

The holy sanctuaries where the Roman Republic worshipped its gods became the temples where the Empire deified its rulers. The marble and bronze of those monuments later came to adorn St. Peter’s, and Mussolini­ built his fascist edifices to evoke imperial architecture. The word we use today as a synonym for pope, pontiff, is adapted from the title of the supreme priest in pre-Republic polytheistic Rome, pontifex maximus. Much of Rome’s art amounts to its own kind of brilliant contradiction: extravagance in the service of piety.