Leopold Stokowski could only have been invented — by Leopold Stokowski.

Magnetic, innovative, and the exception to most rules, starting a century ago Stokowski made the Philadelphia Orchestra what it is today, with a glamour and showmanship that reached listeners well beyond the core classical audience.

So, as the Philadelphia Orchestra forges its post-bankruptcy identity, music director-designate Yannick Nézet-Séguin is looking back to that launching point of the orchestra's international reputation with a four-concert centennial Stokowski Celebration from Thursday through Saturday in the hall where it all began, the Academy of Music.

A step into the past? Not when one realizes that Stokowski premiered works still considered dauntingly modern today, that many of his recordings are still standard setters, and that he lived a life of ceaseless (and often flamboyant) experimentation almost until his death in 1977 at age 95. His Philadelphia Orchestra successor Eugene Ormandy reportedly feared comparisons. Might Nézet-Séguin as well?

The young Montrealer reacts with Stokowskian audacity. "This is never the way I think," he said in a phone interview last week. "It's really to pay tribute, and to place myself in the line of tradition that's in the Philadelphia Orchestra."

Among other things, Nézet-Séguin will conduct such Stokowski chestnuts as Rimsky-Korsakov's Scheherazade (on Thursday), and excerpts from the 1939 Walt Disney film Fantasia — whose soundtrack was recorded with Stokowski mostly at the Academy — in two Saturday concerts, one for young people, the other in which selections were chosen by orchestra patrons.

Most intriguing, the Friday concert re-creates Stokowski's first program with the orchestra, in 1912. It's the one thing about the celebration that might seem dated. Rather than putting the Brahms Symphony No. 1 on the second half, as would happen today, the concert begins with the piece; an overture that might normally raise the curtain — Wagner's Tannhauser — will lower it.

"It'll be interesting to see if it works," said Nézet-Séguin — as if anybody could follow in Stokowski's idiosyncratic footsteps. Or would want to.

Just because the maestro was a cultural icon in the 1930s and '40s — thanks to continually sold-out concerts in Philadelphia and New York, appearances in such films as The Big Broadcast of 1937 and 100 Men and a Girl, and his much-publicized affair with Greta Garbo — doesn't mean he was universally loved. Conductor Arturo Toscanini was so incensed by Stokowski's high-handed interpretations of the classics that he wrote a letter claiming the modern world had known three assassins: Hitler, Mussolini, and Stokowski.

His handshake with Mickey Mouse in Fantasia brought classical music into a populist forum, adding to the belief that Stokowski was more showman than artist. But when he was in front of an orchestra none of that mattered, at least not to now-retired Philadelphia Orchestra bassist Emilio Gravagno.

"Stokowski had a self-assurance that was extremely powerful," Gravagno said. "He didn't have any doubts about what he wanted to do or what he could do."

Though he conducted without a baton, the bassist recalled, Stokowski could focus an orchestra's attention with his thumb and two forefingers clenched together like a drill. Ever practical, Stokowski also demonstrated how to suppress a midperformance sneeze.

With such assurance came a willingness to take risks that might not work out, said West Chester-based recording historian Ward Marston, who knew Stokowski slightly in the conductor's later years. "I don't remember his exact words, but he said, 'If I've ever been a success it's because I've been willing to have more than my share of failures.'?"

The London-born Stokowski was an essentially untried conductor with a church organ background during his tenure with the Cincinnati Symphony Orchestra from 1909 to 1912. But by the time he was appointed to Philadelphia's young backwater orchestra in 1912, his persona as an orchestral wizard was in place, and his impact on the players was immediate — musically and in other ways. (Early on, he is said to have arrived for rehearsal wearing pajamas and reacted imperiously when this was pointed out to him.)

Then there was his strange pan-European accent. "I had a friend in the second violin section, Gus Loeben, who played from 1919 to 1954. He said the accent became more pronounced over the 1920s," says Marston. "Every once in a while, his Cockney roots came through. He'd drop his guard and you'd hear vestiges of that kind of speech. He was extremely mercurial and opaque."

His wildly invented past including being born near Krakow, having connections to Polish aristocracy and relatives who fought for Napoleon, and other picaresque tales that were definitively debunked long before the conductor stopped telling them. One story he seems not to have told in public, only to a few intimates, is that his body bore the scars of childhood malnutrition.

That difficult (if true) past was long buried at the summit of his Philadelphia tenure when he continually challenged audiences with new music (giving the U.S. premiere of the Alban Berg opera Wozzeck in 1931) and dazzled listeners with his gargantuan calling card, Mahler's Symphony No. 8, "Symphony of a Thousand." Stokowski claimed a direct lineage with the piece: As a student in 1910, he had witnessed the composer's rehearsals for the Munich premiere. Or so he said.

In the mid-1930s, as he spent less time in Philadelphia — and more time in Europe with Garbo — the orchestra brought in Eugene Ormandy, who shared duties until Stokowski departed in 1941, having lost his ongoing battles with the orchestra board.

In a 2007 interview, the now-deceased English hornist John Minsker said there was an element of sabotage: For a performance of Bach's St. Matthew Passion, the singers hired in Stokowski's absence were so inadequate that the performance was "an absolute disaster." Still, the break must have come as a surprise to the conductor: He left behind an unfinished house for himself and Garbo in Gladwyne.

Thereafter, Stokowski pursued associations with orchestras great (the New York Philharmonic) and less-than-great (the Hollywood Bowl Orchestra), had a 10-year marriage (his third) to socialite Gloria Vanderbilt, and wasn't forgotten in Philadelphia. During the orchestra's strike in the 1967-68 season, the musicians invited him to give a strike concert at the Civic Center, recalls now-retired concertmaster Norman Carol, then in his first season here.

"He jumped at it. It was a wonderful time to get even with the board members of the orchestra," Carol says. "We had a sellout crowd."

It's widely thought that for a time Ormandy had blocked Stokowski's return. ("You bet your boots," says Carol.) But no longer. He was invited back in subsequent seasons to conduct such high-budget works as Schoenberg's massive Gurrelieder, despite significant infirmity.

"I saw him walking out on the stage and I wanted to help him because he was struggling to walk from the wings to the podium," Gravagno recalls of that 1961 appearance. "But once he got on the podium … what an amazing change. He was totally in control." By several accounts, his authority was effortless. He didn't even have to speak.

Eventually, Stokowski returned to his native England, concertized periodically, and had a recording contract that would have taken him through his 100th birthday. Marston was there in 1975 for his last recording, of Scheherazade, when the conductor was 92. The strength of his will at that point is particularly remarkable, given the effects of age. During a startlingly intimate conversation with Marston, Stokowski said, "You know when you're not sure if you're sleeping or waking? That's what it's like for me most of the time."

With so much music over the dam, so many dots to connect in the Stoky psyche, it's hard to know what to take away from this flawed giant, whose renewed influence is likely to be felt well beyond this week's festival.

With theater director James Alexander on hand to present newly created high-definition video effects in the concerts, Nézet-Séguin is obviously keen to explore some of Stokowski's own ideas about visual presentation — "as long as the orchestra is still the main feature," he says.

"Having Fantasia with orchestra underneath is fine. That's a landmark in the history of the orchestra. But apart from this I think we can win by combining different forms of art, now that video is more accessible."

Contact David Patrick Stearns at dstearns@phillynews.com.

Music   Stokowski Celebration 8 p.m. Thursday, 2 p.m. Friday, 11:30 a.m. and 8 p.m. Saturday at the Academy of Music, Broad and Locust Streets. Tickets: $10-$109. 215-893-1999 or www.philorch.org.