Musical performances attended by a large number of great musicians?

I have never seen a detailed listing, but it is generally agreed that every violinist worth two cents and most pianists of equal value were at Jascha Heifetz's New York debut.

Second thought (oh good, I could edit) - I seriously doubt ANYTHING could top the Last Night at the Old Metropolitan Opera House. Almost every living opera great was there, as well as almost every living conductor who had conducted a performance. Many of them performed in solo or ensemble numbers. And there was a group photograph taken of most of them on the stage (as well as one of Licia Albanese placing a kiss on the floor as she walked off the stage.)

Yet another edit. The Kolodin history of the Met does not have a complete listing of who attended, but does include a picture of the greats on the stage. I count 79 heads, give or take a few. Kolodin lists the following on the first three rows:

Rise Stevens

Marjorie Lawrence

Elisabeth Rethberg (debut 1922!)

Martha Lipton

Lotte Lehmann

Helen Jepson

Nannette Guilford

Hertha Glaz

Vilma Georghiu

Anna Case (first sang in 1912-13 season)

Rose Bampton

Marian Anderson

Alexander Kipnis

Raoul Jobin

Frederick Jagel

Richard Crooks

Eugene Conley

Mario Chamlee

John Brownlee

Richard Bonelli

Well- there are all our Geek Meets - the conventions of each particular instrument or other musical specialty. When I go to the National Flute Association conventions, there are several thousand flutists there - and just about anyone who is of importance in the flute world is there. I would assume that each other instrumental convention is similar. So to US, all our famous colleagues, principal players, etc. are in one spot for a few days . . . and at each others' performances. Above my head where I am now sitting, is a photo of over 2,000 of us - we hold the Guinness records of world's largest flute quartet, conducted by Sir James Galway - and on each of the 4 parts were an odd but exciting agglomeration of college kids, professional players, and superstars. Not quite what you had in mind, Del - but as close as *I* can come from personal experience.

I would have to plow through some things like the Musical Book of Lists, or Through the Looking Glass to see if I can find others. We just saw the indie film about Stravinsky and Chanel - I wonder who was at that first Rite of Spring performance??

Schoenberg and Webern are the only two half-decent composers from your list; but a truly remarkable event...for a very flawed piece of music.....Mahler was (quite rightly) revered as a conductor rather than a composer in his own time

The premiere of Strauss' Salome (May 16,1906 in Graz):

Puccini

Mahler (with Alma)

Zemlinsky

Schoenberg

Berg

The widow of Johann Strauss

Thomas Mann's Adrien Leverkuhn

Adolf Hitler also claimed to be there