How many movies have Humphrey Burton and Leonard Bernstein collaborated on?

They have worked on 24 movies together! Their first movie together was Bernstein in Vienna: Beethoven, The Ninth Symphony (1970) while their highest rated movie together was Mahler - Symphonies Nos. 1, 2 & 3 (1973). They have not worked together since Brahms Academic Festival, Tragic Overtures/ Variations on a Theme by Haydn/Serenade No. 2 (2007). They are most known for their music films together.