But, by most accounts, Mozart was near the bottom when he wrote it: broke and in debt. His audiences had become interested in other composers. Austria was at war with Turkey. And his newborn daughter had just died.
Still, Mozart was determined to do something revolutionary. That comes in the final movement of the Jupiter Symphony with the composer's use of counterpoint, or weaving together two or more different melodies. Mozart uses five different melodies simultaneously in the Jupiter, making it a challenge for any orchestra that takes it on.
Some have said the Jupiter sums up what had happened in symphonic music up to that point, and that it foreshadows the work of Beethoven. But more than that, it's exuberant and introspective, charming and complicated — a lot like life itself.