In July, he died. On Nov. 9, the Berlin Wall came down.

Then, on Christmas Day, Leonard Bernstein, Karajan's old rival, summoned orchestra members from Munich, Dresden, Leningrad, Paris, and New York to Berlin for the official concert celebrating the fall of the wall - a historic performance of Beethoven's Symphony No. 9. Had the mighty Berlin Philharmonic fallen as well?

It hadn't. In fact, what had once been the orchestra of the Third Reich (Karajan once was a member of the Nazi Party) was liberated.

The Berlin Philharmonic is still an orchestra of captivating virtuosity, its sound silken and dazzling. But Berlin is a radically different city than it was 20 years ago, and the Philharmonic is just as radically different an orchestra.

The once Aryan orchestra now boasts musicians representing 40 nationalities. And like Berlin in the two decades since German reunification, its leading orchestra is feisty and cutting edge - yet, deep down, doggedly traditional.

The challenge, then, for the Berlin Philharmonic is not only to remain the symbol of the city but also to be a model for cultural and social unification in an anxious metropolis, where old and new, German and foreign influences, excitingly, if also tensely, coexist.

That's where Simon Rattle comes in.

When Rattle became the orchestra's principal conductor and artistic director in 2002, after 18 years with the City of Birmingham Symphony in England, he found an ensemble fiscally bankrupt yet artistically vibrant after a rocky but not undistinguished 13 years under Claudio Abbado. The Italian conductor had begun a modernization project, and now the organization thought it might be ready for a big musical adventure.

Adventure it got - perhaps more than the players, audiences, and critics bargained for. Welcomed as "Sunny Sir Simon," Rattle took this elite orchestra places it had never dreamed of - to schools in poor immigrant neighborhoods and maximum security prisons. After a while, the media began to turn on Rattle, finding Sunny Sir Simon's conducting all empty smiles.

"It's been an interesting journey," Rattle said last week in a phone interview. "Slowly and surely we have come together through honeymoons and the opposite. I remember Karajan said that with an orchestra like this, the first five or 10 years are tradition. I didn't quite believe him. But after what has sometimes felt like moving at the speed of tectonic plates . . . we now have a tradition to build on."

Once more the darling of Berlin, Rattle credits at least some of the turnaround to Brahms. A year ago, he conducted a cycle of the four symphonies, music that has been in the orchestra's collective psyche since its 1882 founding, to high acclaim. The symphonies were recorded live and have just been released as a boxed set on EMI Classics.

The playing is, as it always is with this orchestra, superb. And it is easy to see why Rattle finally won over doubters. There is something for everyone. The sound is powerful and protein rich but also graceful. This is Brahms with vitality and also an autumnal glow, Brahms that is heavy and serious but not oppressive, Olympian Brahms but not unapproachable Brahms. It is, in the best sense, Berlin Brahms, and Berlin no longer doubts that it wants more. Last month the self-governing orchestra extended Rattle's contract through 2018.

But Rattle is quick to point out that the Berlin tradition he has revitalized isn't quite so clear cut as people seem to think. For one thing, he oversees an increasingly young and international orchestra. Musicians, Rattle says, have been hired without ever having played in an orchestra. And even those with orchestral experience, including principals, have arrived without having ever played certain key works, such as Beethoven's Fifth Symphony.

The orchestra's DNA, somehow, gets transplanted into the new players, but not without the occasional genetic mutation.

"Sometimes we have to search for that style," Rattle says, "because there are actually many ideas about what the orchestra's style had been. This is a listening orchestra. Many American orchestras will say, 'Just give us a clear beat.' But that doesn't work here. You must find a way to invite them to play, and I learned to be a lot freer and less controlling. Now that we're doing these Brahms symphonies again for the [U.S.] tour [which ended this week], we're already rethinking them. The process never stops."

What has also made a difference is that Rattle is now part of his community. At first, he split his time between England and Germany and didn't speak German. But now he has settled in Berlin with his third wife, Czech mezzo-soprano Magdalena Kozena, and their two sons.

Rattle also is evangelical about spreading the word across much wider expanses, with his Philharmonic's "digital concert hall." This is the first orchestra to broadcast all its concerts, pay per view, in high-definition video and sound on its Web site.