In the summer of 1788, Wolfgang Amadeus Mozart composed three four-movement symphonies in the space of two months. Given the composer’s situation at the time, a financial condition best described as debt-ridden, one would assume he had been handsomely commissioned to spend precious weeks laboring over lengthy, complex scores. That assumption would be wrong. No one knows for certain why Mozart composed the works we know as his last symphonies: No. 39 in E-flat, No. 40 in G minor, and No. 41 in C, the latter nicknamed “Jupiter.” There is no record of a commission, and the symphonies were not performed in his lifetime. Mozart died in 1791. Success and Fading Fortune Upon his arrival in Vienna from Salzburg seven years earlier, Mozart had been feted and acclaimed as a fresh young talent. Commissions and students abounded. Now 32, he could no longer lay claim to youthful status. Two other …