[EDNOTE. Carolyn Kunin sent in her announcement of the correct answer at almost the same time that Anthony Stadlen, unbeknownst to her, submitted that answer to the List. -- SES]
The time for responses to the Quiz has now elapsed, so unfortunately no one wins the prize. The correct answer is Diaghilev was responsible for all those ballet scores composed by Stravinsky, because he commissioned them.
Since there was no prize, as promised her is the surPrize (from Wikipedia article on Igor Stravinsky)
In other words: yesterday was Igor Stravinsky's 130th Birthday and I have to confess, this came as a surprise to me, too - by coincidence Richard Taruskin sent me an email informing me of the date after I had already posed the Quiz. Had someone won the contest I would have sent them a nice cd recording of Petrushka played on two pianos as performed at the Ojai Festival this year which I was fortunate enough to have attended.
As for what I had in mind for the surprise, I hate to admit it, but I hadn't actually gotten that far.
Thanks for playing - it was great fun,
Carolyn