VENICE, March 14 — Although you can still see the recesses in the walls where the hinges of the portals once hung, the Venice ghetto has not been a prison since Napoleon seized the city and tore down the gates in 1797. Today, no barrier or signpost marks where Venice ends and its ghetto begins. Cross a canal on an arched bridge, duck through a sottoportego (an alley tunnelling through a building), disappear down a vent in the urban fabric — you come and go just like everywhere else in the maze of this island city.

But linger long enough in the Campo di Ghetto Nuovo, the generous, frayed, tree-flecked plaza that anchors this corner of Cannaregio (the quiet northwest quadrant of the city) and you’ll feel the wall of the past closing in. Half a millennium of history does not transpire without stamping the soul of a place.

Established by decree of Doge Leonardo Loredan on March 29, 1516, the Venice ghetto was one of the first places where people were forcibly segregated and surveilled because of religious difference. The term itself originated here; the area had been used as a foundry (“geto” in Venice dialect), and over time the neighbourhood’s polyglot residents corrupted the word to ghetto.

I travelled to La Serenissima in December to see how the city was gearing up for the anniversary of the establishment of the ghetto. A major exhibition called “Venice, the Jews and Europe: 1516 to 2016” (on view from June 19 to November 13) was being planned for the Ducal Palace, and during the last week of July, Shakespeare’s Merchant of Venice will be staged (in English) for the first time in the confines where its most hallucinatory scenes take place. Venice being Venice, there will also be glittering parties, celebrity-filled fundraisers and fancy dress galas, starting with the invitation-only performance of Mahler’s First Symphony at La Fenice opera house March 29.

But in the course of my visit, what I became most curious about was the mood of the current Jewish community of 450 people. Venice is such an impossibly beautiful fantasy, it seems astonishing that ordinary people, Jews among them, actually live there. How, I wondered, did deep-rooted Jewish families feel about their past — and future — in this ancient, vulnerable city?

A canal in the heart of Venice, Italy, February 27, 2016.

My first answer came inside the humble, rectangular sanctuary of the circa-1532 Scuola Canton, one of five synagogues still standing in the ghetto. The synagogues are open to the public only as part of guided tours offered by the Jewish Museum of Venice, and that morning just three of us (two other Americans and me) had signed up for the 10.30 tour in English. We were standing with our guide, Silvia Crepaldi, admiring the golden spiralling tree-trunk columns that support the arch over the bimah (podium), when the subject of rising sea levels came up.

“The city will be empty before it sinks,” Crepaldi said ruefully. “Venice is shrinking before our eyes.”

The urban exodus of both Jews and gentiles has been going on for some time, although the pace has accelerated in recent years.

When the ghetto was at its height in the 17th century, 5,000 Jews from Italy, Germany, France, Spain and the Ottoman Empire carved out tiny, distinct fiefs, each maintaining its own synagogue, all of them crammed into an acre and a quarter of alleys and courtyards. Confinement was a burden, but it also provided an opportunity for cultural exchange unparalleled in the diaspora. As Jan Morris, a Venice devotee and one-time resident, writes in The World of Venice, the city was a “treasure-box” full of “ivory, spices, scents, apes, ebony, indigo, slaves, great galleons, Jews, mosaics, shining domes, rubies, and all the gorgeous commodities of Arabia, China and the Indies.”

Jewish merchants and bankers were vital to the flow of these commodities, but as Venice declined, the Jewish presence dwindled. By the outbreak of World War II, Jewish Venice had shrunk to 1,200 residents. Today, with the city’s total population hovering around 58,000 (down from 150,000 before the war), there are about 450 Venetian Jews left, only a handful of them residing in the ghetto.

“So now the ghetto is just a shell?” I wondered aloud as Crepaldi led us across the campo, over a bridge, down a street of intriguing-looking shops, and into a tighter, grimmer square (the Campiello delle Scuole or “little square of the synagogues”), flanked by the two Sephardic scuole.

Inside Scuola Grande Spagnola a synagogue in the Jewish ghetto of Venice, Italy, February 28, 2016.

The answer to my question was revealed inside one of these: the sumptuous Scuola Grande Spagnola (Great Spanish Synagogue), possibly the work of Baldassare Longhena, the renowned 17th-century architect of Santa Maria della Salute. After we had gazed our fill at the elliptical coffered ceiling and the black-columned pediment that frames the ark of the covenant; after we had craned our necks to glimpse the cherry wood balustrade and diamond-hatched panels that screen the upstairs women’s gallery; after our eyes had bathed in the silver gleam of candelabra and the soft glow of crimson-curtained bottle-glass window panes, Crepaldi pointed to the brass plaques affixed to the pews. “These are the names of families who pay to rent their own bench sections,” she told us. “These families still pray here. This synagogue is used in summer, and in winter they switch to the Scuola Levantina because it’s heated. The Venetian Jewish community may be small, but it’s still strong.”

Calimani and Sullam — two of the surnames inscribed on those plaques — appeared in tiny letters by the buzzer I pressed at 10 o’clock the next morning. Riccardo Calimani, the esteemed historian of Italian Jewry and the author of a book about the Venetian ghetto, had given me very precise directions to his home off the Strada Nuova (a rare rectilinear thoroughfare stocked with shops catering more to residents than tourists).

What Calimani had neglected to say in his email is that he lives in a palace: a light-bedazzled, soaring-ceilinged, art- and book-lined Renaissance suite overlooking the Grand Canal. As he ushered me into his princely study, the ample, urbane Calimani struck me as a kind of latter-day Jewish doge.

“My father’s family arrived in Venice from the north of Italy in 1508,” he said, slowing his Italian down to a tempo I could follow. “My ancestor Simone Calimani was the author of a trattato morale [moral treatise], printed in the 18th century when Jewish publishing was flourishing here. My grandfather was the cantor in the Scuola Levantina, even though our roots are not Levantine but Italian and German.” The Venetian history of the Calimani family, I realised, coincides almost exactly with the history of the ghetto.

The palace belongs to his wife’s family, the Sullams, Spanish Jews who took refuge in Venice after the expulsion from the Iberian Peninsula at the end of the 15th century. I knew, from reading Calimani’s The Ghetto of Venice (1988), that Italian and German Jews, the first and poorest to settle in Venice, had been consigned to selling rags and running pawnshops, while the great merchants of Venice were later arrivals from Spain and the Levant.

Riccardo Calimani, a historian of Italian Jewry who wrote a book about Venice's Jewish ghetto, at his studio in Venice, Italy, February 27, 2016.

With tantalising fragrances wafting out of the hidden kitchen and the velvety light of winter burnishing thousands of leather spines, I could practically taste the history that had made this room possible. The palace may be extraordinary, but the convergence of cosmopolitan currents in the Calimani/Sullam household is quintessentially Venetian.

Their families’ abandonment of the ghetto is also typical. As soon as the ghetto was abolished in 1797, Jews with means fled the high-rise tenements — the tallest buildings with the lowest-ceilinged apartments in Venice — for more elegant, and spacious, parts of the city. But the ghetto remained the anchor of Venetian Jewry. Since travel by gondola was deemed permissible on the Sabbath, the observant had no trouble floating back each week to pray at the scuola of their choice.

Today, the Jews of Venice, although still a proud (if dispersed) community, are invisible. (The black-garbed Hasids you see in the campo are not Venetian but followers of the Chabad-Lubavitch movement who have resettled here from other parts of Europe and the United States.) Calimani, like every local Jew I spoke to, said he moves unremarked in and out of Jewish circles. “The Venice ghetto,” he told me, “was always more open to the city than the Roman ghetto, which was beset by the conversion mania of the church.”

The dispersal of the community had the unexpected benefit of sending me into unfamiliar neighbourhoods in pursuit of interviews. I had been in Venice twice before, but far from growing accustomed to its gorgeous strangeness, I found it endlessly fascinating just to thread the maze, and inevitably get lost in it, on my way to appointments.

The Airbnb my wife, daughter and I rented just off Campo SS. Giovanni e Paolo — the heart of Castello, a still quasi-authentic quarter of working families, schools, neighbourhood bars and the municipal hospital — is perhaps half a mile as the crow flies from the flat of Donatella Calabi, a professor of urban history who curated the exhibition “Venice, the Jews and Europe: 1516 to 2016.” But even though Calabi had emailed me a map with arrows pointing the way, it still required several forays across the nearby Campo Santa Maria Formosa before I hit on just the right “calle” (street in the Venetian dialect).

No matter; it just gave me more angles from which to admire this perfect urban plaza with an austere whitewashed church rising in the centre and a perimeter of magnificently crumbling palaces now occupied by restaurants, hotels, banks and the delightful 16th-century house-museum of the Fondazione Querini Stampalia.

The Campo di Ghetto Nuovo, a plaza that anchors Cannaregio, the northwest quadrant of Venice, Italy, February 28, 2016.

As we sat by the windows of her top-floor apartment watching the dome of San Marco go grey against the December dusk, Calabi spoke with animation of the coming exhibition at the Ducal Palace. “The ghetto provided an incredible occasion for cultural exchange” she said, “and the exhibit will focus on that exchange within the ghetto itself, between the ghetto and the city, and with the rest of Europe.” Artworks including Carpaccio’s Predica di Santo Stefano (St Stephen’s sermon) on loan from the Louvre, virtual reconstructions of the ghetto in various periods, and sacred books will conjure up the rich complexity of this exchange.

Calabi became more sombre when the conversation turned to the present. “Renaissance scholar Francesco Sansovino wrote that for the Jews, Venice was ‘quasi una vera terra di promissione’ — practically a true promised land,” she said. “But today Jewish Venice is a small community within a small city. The 500th anniversary is an occasion not to celebrate — you don’t have a festival for a ghetto — but to commemorate. An unbroken stretch of 500 years of history will not happen again soon.” — The New York Times