IN 1516, when the Venetian authorities ordered the city’s Jews into an area near a foundry, they gave them just 48 hours to move. They also forced them to pay their new landlords 30% more rent than the outgoing Christian tenants. A Venetian word meaning “foundry” may have given rise to the term “ghetto”, which over the years has taken on wholly negative connotations. The 500th anniversary of that fateful event scarcely invites celebration. Yet it has inspired in Venice itself several intriguing, and controversial, initiatives of which the highlight is an exhibition opening at the Doge’s Palace on June 19th.

Some visitors will find the show surprising, even shocking. The curator, Donatella Calabi, argues that viewing the Venetian ghetto through the prism of the Nazi-imposed ghettos of the Shoah is misleading. Her exhibition shows how the ghetto was created at a time of crisis in the old Venetian republic, or La Serenissima, when its governors became wary, not just of Jews but of all deemed to be outsiders. In confining them, they were doing what they also did to non-native merchants including Greeks, Turks, Armenians, Persians and, ironically, Germans. The Turks particularly, says Ms Calabi, were subject to rules “stricter perhaps than those imposed on the Jews”. Quarantining foreigners was done partly for their own safety (murderous clashes between merchant communities were not uncommon) and was “the same as the discrimination exercised at the time in all the great commercial cities: London, Seville and Antwerp”.

But, as some Venetian Jews have argued, most of their forebears were not outsiders (some arrived in the 14th century). Nor were they citizens of an empire, the Ottoman, intermittently at war with Venice. Moreover, with the passage of time, the confinement of Venice’s Jews continued, though the original motive was gone.

The exhibition does not gloss over the hostility they attracted. Two unobjectionable depictions of Jews by Carpaccio alongside Bellini’s “Drunkenness of Noah” highlight the latter’s anti-Semitism: the patriarch’s sons have caricature Jewish noses and the bulbous tip of Ham’s is cruelly emphasised by light. Another exhibit tells of the Jews’ Channel in the lagoon, dug so they could remove their dead for burial without crossing the centre of Venice, where louts would stone the waterborne hearses.

It is evidence of how much worse conditions became for Jews elsewhere in the Mediterranean that successive waves of refugees fled to the Venetian ghetto. In the 17th century its population reached 6,000.

The intermingling of different Jewish traditions produced five synagogues, each with its own rites, and the development of a rich, hybrid cultural life made even more varied by contact with the surrounding Christians. The first complete edition of the Babylonian Talmud was published in Venice, by a Christian (Jews being forbidden to work as printers). And among the ghetto’s residents was Sara Copia Sullam (c.1592–1641), a poet and essayist whose literary salon was open equally to Jewish and Christian intellectuals. The exhibits at the Doge’s Palace include an ornate Venetian Jewish marriage contract which has an imagined representation of Jerusalem. But this Jerusalem has a canal in it with a bridge under which a little boat is about to disappear.

Beit Venezia, an NGO set up to breathe new life into the ghetto’s multicultural heritage, has seized on the quincentenary to sponsor an international symposium on the ghetto as a global metaphor and, more provocatively, to put on the first staging in the ghetto of “The Merchant of Venice”. The play opens on July 26th. On the second day of its run, a mock court hearing is to be held, with real lawyers and a jury led by Ruth Bader Ginsburg of the American Supreme Court.

From the square where the play will be staged, the dome of the Scola Canton, one of the synagogues, can be seen tilting alarmingly. It is the most visible sign of the deterioration of what David Landau, an arts philanthropist who settled in Venice seven years ago, calls “the most important Jewish heritage site in Europe”.

The wall behind the German synagogue, the oldest and arguably prettiest, is crumbling into an adjoining canal. A crack has opened in the floor that Marcella Ansaldi, the curator of the nearby Jewish Museum, says is growing alarmingly. Woodworm is eating at the timber skirting boards. “We may soon have to stop visits,” she says. At the Italian synagogue, the windows can no longer be opened because the frames are so crooked they could not be shut again.

Restoring three of the five synagogues and linking them to the museum would cost an estimated €12m ($13.5m). Venetian Heritage, an American NGO, has raised €1m. The city’s Jewish community has asked Mr Landau to help find the rest. Persuading anyone, let alone fellow Jews, to pay for the preservation of a locality with such hateful associations as a ghetto will not be easy. But it would be tragic to lose to decay and neglect such a beautiful and culturally variegated corner of Europe.