Was Mozart the first teenage music pirate, ar ar?
Well Gregorio Allegri's Miserere was composed exclusively for services in the Sistine Chapel and apparently the Catholic Church threatened anyone who performed or wrote it down outside the Vatican with excommunication.
In 1770, when Mozart was 14, he visited the Vatican and heard the music two or three times (as I understand it, though legend has it he only heard it once). He duly returned home the following year and transcribed it all from memory.
I'm not aware of any record of his excommunication for his piracy. Perhaps the relatively newly inaugurated Clement XIV was too pre-occupied with politics to think about a boy genius pirate? One of the reasons Giovanni Vincenzo Antonio Ganganelli was elected Pope Clement XIV, at the end of three months of Machiavellian manouevres in the papal conclave, was that he was not a Jesuit and a variety of European monarchs had been heavily lobbying against having a Jesuit Pope.