The Jupiter Symphony is Mozart's last, and with its humor, exuberant energy, and unusually grand scale, earned the symphony its nickname—for the chief god of ancient Roman pantheon.
1788 was a time of great financial and physical difficulty for Mozart. Despite all of that, the music of this final period amazes. His last three symphonies (Nos. 39, 40, and 41) were written in quick succession all in one summer in 1788. Mozart would die only three years later.
There's a lot we don't know about Jupiter and the other two accompanying symphonies. Did Mozart actually hear his final symphonies performed? Who was it written for, and why?
It's uncertain whether or not the symphonies were performed in Mozart's lifetime. Also, Mozart rarely composed on a whim. He typically wrote on commission or created new pieces for friends. Such transactions were cataloged in the composer's letters and writings... but the historical record for the summer of 1788 is completely silent.