Piano Forum

I'm just curious about Mozart's Fantasia in C minor--it's my favorite piece by him, and I'd like to know more about it. Why is it so different from so many of his other works (I only know of a very, very, very few works that even come close in their depth, shadow, and emotion--Sonata in a minor, Concerto in D minor, C minor Sonata)? What event in his life drove him to write something so dark--after all, it seems to compete with anything Beethoven and Chopin wrote as far as emotion, and Mozart's style makes it all the more powerful. So can anyone explain this piece? Thanks!