In a way, it began with Napoleon's conquest of Venice in 1797. Then, almost a century later, the idea itself was dreamed up by artists over coffee at Florian's on the Piazza San Marco. But first there was the matter of relocating the elephant named Toni.

These disparate events led to the birth in 1895 of the Venice Biennale, which for as long as anyone can remember has been accepted as the art world's most important gathering. The international exhibition, opening for the 53d time next Sunday, reliably makes big waves, if only for the reliable fretting from many of its 200,000-plus visitors that it no longer makes big waves.

This time, with a bold contribution from the Philadelphia Museum of Art, waves seem assured. American artist Bruce Nauman and the museum are collaborating on a three-venue show likely to provoke, stump, anger, and intrigue visitors with philosophical inquiries through neon, a newly commissioned audio installation, and other media.

As the U.S. representative at the Biennale, the museum is relishing this moment on the art world's big canvas in the city where, Henry James observed, "art and life seem so interfused."

"It gives the museum recognition on an international stage as a player in the contemporary art world," says Alice Beamesderfer, the museum's interim head of curatorial affairs. "I can say that Venice will introduce the museum to many collectors and supporters who may not know us yet. In our fund-raising for Venice, we have people who gave who have never given to the museum before."

The selectively reclusive Nauman, 67, arrives in Venice with a concise show and with his worship by fellow artists nearly absolute.

"In terms of his enduring influence, you can hardly think of an artist today who doesn't admit to a debt to Bruce Nauman. And not just American - if anything, his reputation is even stronger elsewhere," says Constance Lewallen, adjunct curator at the University of California, Berkeley, Art Museum and Pacific Film Archive.

And yet his name is little recognized beyond the inner circle. Is Nauman an artist's artist?

"He's not like Rodin or someone like that. I don't know what his appeal is outside of the avant-garde art world," venerable art critic Arthur C. Danto says. "The famous thing he said - that if I am an artist, then whatever I do in my studio is art, that famous quotation - it sort of opened up possibilities that people hadn't thought of before. He's a grandfather of a certain sculptural language and attitude in art."

Nauman makes a deep connection with many viewers.

"It's a time-consuming process. You have to slow yourself down and pay attention," says Paul Schimmel, chief curator of the Museum of Contemporary Art, Los Angeles, which has presented three Nauman shows. "But it's interesting. You have currently in Philadelphia an exhibition of Cézanne and his legacy, and I understand viewers are taking a great deal of time looking back and forth between Cézanne and the other works, and it has made them look more carefully and thoughtfully than they would otherwise. And there is no question in my mind that Nauman is our Cézanne, an American Cézanne, an artist of that significance in terms of impact and influence."

The idea for working with Nauman began gestating under longtime Art Museum director Anne d'Harnoncourt, who died a year ago and to whom the show's catalog will be dedicated. The museum's scheme for the U.S. Pavilion was chosen last year from 11 proposals submitted to the State Department.

The Art Museum also curated the 1988 Jasper Johns show at the Biennale; before that, only one other Philadelphia institution had undertaken the honor - the Institute of Contemporary Art, in 1980. (The art exhibition switched back to odd years in 1993.)

Janet Kardon, the institute's director from 1979 to 1989, says the show was "a big step for the ICA. It meant the institution was entering the international dialogue." She vividly remembers the moment the installation was set to begin.

"I arrived that day, and the workers said, 'I am afraid we cannot work today. We are on strike.' Tears started running down my cheeks. They saw that and said, 'Don't cry, don't cry. We'll strike during lunch.' " They did, and the show opened on time.

For the Nauman show, curator of contemporary art Carlos Basualdo has been battling rain for weeks in Venice. "Bruce Nauman: Topological Gardens," which will open next Sunday and run through Nov. 22, will occupy more than just the U.S. Pavilion; pieces will also be set on spaces at the Università Iuav di Venezia at Tolentini and the Università Ca' Foscari.

The works will be organized into three threads: "heads to hands," "fountains to neons," and "sound to space." Topological refers to the mathematical study of geometric properties preserved despite stretching or deformation of shapes.

However that relates to gardens, Venice, and art - and whatever the critical reception - exposure for the Art Museum will be on a grand scale. The Biennale, an early foray into cultural tourism, has played to big crowds since 1895 - falling as low as 76,000 in wartime 1942, peaking in modern times in 1980 at 365,000, but most often drawing around 200,000. Its ripples travel far through an astonishing media presence: In 2007, 5,691 journalists attended during its six months.

The idea for Venice's international art exposition, if the legend is to be believed, was hatched in 1893 by local artists over coffee at Caffè Florian. Napoleon had unwittingly paved the way when, after the Republic of Venice's surrender in 1797, he ordered part of the city razed and marshes drained for the creation of the Giardini di Castello - the site of the Biennale.

By 1895, Toni the elephant - long resident in a building in the neighborhood - and some cavalry stables had been moved to make way for a pavilion with 11 galleries. The first exhibition drew 224,000 visitors.

National pavilions were added early on. The Belgian was first in 1907; German, British, and Hungarian buildings came next. The Giardini area hosts 29 national pavilions today, and programming one, as the Art Museum is doing, is a coveted honor.

But in addition to the Giardini, the Biennale has spilled over into the vast Arsenale (a historic shipyard complex) and other areas of the city. The director of the 53d exhibition, called "Making Worlds," is Stockholm-born writer, curator, and administrator Daniel Birnbaum. The show, spread through the Palazzo delle Esposizioni in the Giardini and the Arsenale, includes more than 90 artists.

Thousands of important works have met their publics at the Biennale, where many art lovers got their first glimpses of cubism, Postimpressionism, futurism, precisionism, abstract expressionism, pop art, and so on. Yet Venice also has been infamously timid, rejecting work by the young Picasso in 1905 as too novel; he finally was shown in 1948.

The Biennale has added sections for music, film, architecture, dance, and theater, but art retains the largest profile, and its scope has evolved since 1895. Now it is all about contemporary work. But some years - such as 1954, when d'Harnoncourt's father, René, was commissioner of the U.S. Pavilion as director of New York's Museum of Modern Art - have offered great stylistic range. In 1954 you could see the Impressionists but also American abstract expressionist sculptor David Smith. The U.S. Pavilion was packed with works of Ben Shahn, the social realist whose work explored Sacco and Vanzetti, World War II, and, later, the Rev. Dr. Martin Luther King Jr.

Politics and art often elbow each other for the spotlight. When Chilean art spread into the entire city in 1974 as a protest against dictator Augusto Pinochet, it was a stark counterpoint to the 1930s, which featured walk-ons by Hitler and Mussolini as leadership of the Biennale passed to the fascist government.

"It is as much a political platform as an aesthetic one," Kardon says. "I think it's partly because of the physical nature of the Biennale. The part in the Arsenale is more international, it's curated by a single curator, and the work is presented regardless of origin. But in the Giardini, the work is presented in each country's pavilion, and so when we see England's pavilion, we think, 'Oh, my gosh, this is England. What do we think of England?' "

Palestinian statehood may be an open question, but in 2003 a Palestinian presence was established with an installation called Stateless Nation, consisting of giant passports spread out over the grounds.

Controversy keeps coming. In response to what it calls "blasphemous" art, the Vatican has announced a desire to establish a pavilion for the 2011 Biennale. Pope Benedict XVI has exercised a strong voice as both music and art critic. Having spied Zuerst die Füsse, a work by German artist Martin Kippenberger depicting a frog on a crucifix in a museum in Bolzano, Italy, the pope supported the position of Franz Pahl, president of the regional government, who called the work "a disgusting piece of trash."

Nauman's work might be no less confrontational. Occasionally sexual (a neon idée fixe evokes a man with erect penis), often enigmatic to an extent that requires knowledge of his theories, Nauman has expressed ideas in film, photography, light, sound, drawing, and sculpture that borrow form from mundane objects. One favorite raw material is his body, which he has manipulated and then photographed. Wordplay and puns are frequent, a playfulness that sometimes belies the seriousness of the topic being explored.

What is the core concern of Nauman's work?

The artist has deflected easy categorization with a perhaps overly generous definition of art: "Art is what an artist does," he has said.

That's not quite the same as saying that anything an artist does is art, but it's close.

Which might make a Nauman partnership with the Art Museum, home to a rather plush aesthetic exemplified by its itinerant Impressionist blockbusters, European decorative arts, and colonial American furniture, seem unlikely.

But the museum is almost singularly suited to Nauman as the repository for one of the most disruptive forces in the history of art: Marcel Duchamp, whose Nude Descending a Staircase, No. 2 was a source of controversy, as was the urinal he appropriated as art.

Nauman does not claim Duchamp as an influence, but the wink and nod that take place across the decades are unmistakable; each has manipulated and mastered the idea that art can be anything.

The Duchamp gem Étant Donnés, owned by the Art Museum, is as much an experience as Nauman's participatory installations (some of which contained video elements, which were to become a common tool in contemporary art).

Encountering Étant Donnés, you walk up to a pair of wooden doors in a brick archway. Through two small holes in the doors, what you see is startling: A life-size mannequin of a naked woman lying on twigs and leaves. In her left hand she holds an old-fashioned gas lamp. As in a lot of Nauman, the observer becomes participant, forcing a level of engagement far beyond that of an oil on a wall. You find yourself stopping, staring, thinking, looking again.

Duchamp and Nauman dovetail - and will do so literally this year in Philadelphia. Étant Donnés is the centerpiece of an exhibition by modern-art curator Michael R. Taylor opening at the museum in August and running through November, when the museum will pack up the Nauman show in Venice and, it hopes, ship parts of it home for a different version of the show.

Étant Donnés will remain in place, creating with Nauman what d'Harnoncourt referred to as works having "conversations" with each other.

"It's very much in the spirit of Bruce Nauman, and probably Bruce Nauman is unthinkable without it," Danto says of Étant Donnés. "I think there is a direct line of descent from Duchamp to Nauman, and from that perspective this is a very natural thing for Philadelphia."

A lingering consequence of prolonged exposure to both artists and their real-world objects in made-for-art settings is that you begin to reconsider what you've overlooked in the real world that may have been hiding as art all along.

The sensation, of course, has been true in Venice for a very long time, as Henry James knew.

The Inquirer in Venice

Inquirer culture writer Peter Dobrin will be at the 53d Venice Biennale through its opening days next week - talking with American artist Bruce Nauman, spending a day with U.S. Pavilion curator Carlos Basualdo of the Philadelphia Museum of Art, and covering the art and social scene at the world's largest international art exhibition. Read his work in the pages of The Inquirer, on Philly.com, and on his blog, "ArtsWatch," at www.philly.

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Contact culture writer Peter Dobrin at 215-854-5611 or pdobrin@phillynews.com.