Part of the service used in the Pope's chapel at Rome
is sacredly guarded and kept with great care in the
archives of the chapel. Any singer found tampering
with this "Miserere" of Allegri, or giving a note of it to an
outsider, would be visited by excommunication. Only
three copies of this service have ever been sent out.
One was for the Emperor Leopold, another to the King
of Portugal, and the third to the celebrated musician,
Padre Martini.

But there was one copy that was made without the
Pope's orders, and not by a member of the choir either.
When Mozart was taken to Rome in his youth, by his
father, he went to the service at St. Peter's and heard
the service in all its impressiveness. Mozart, senior,
could hardly arouse the lad from his fascination with the
music, when the time came to leave the cathedral. That
night after they had retired and the father slept, the boy
stealthily arose and by the bright light of the Italian
moon, wrote out the whole of that sacredly guarded
"Miserere" The Pope's locks, bars, and excommunications
gave no safety against a memory like Mozart's.


From Anecdotes of Great Musicians by W. F. Gates