One of the great musical treasures of the Vatican is the Miserere of Gregorio Allegri. Allegri was director of the Sistine Choir. For the season of Lent, he composed a setting of Psalm 50 (Psalm 51 in the King James and other Protestant versions) for Tenebrae, a special liturgical service of readings and psalms celebrated only during Holy Week. This piece of music was also jealously guarded by the Vatican. It was forbidden to make copies and only the Sistine Choir had access to it.
In the 18th century, as the boy Mozart was astounding Europe, he attended a papal tenebrae service at which Allegri’s Miserere was sung. Afterwards, he went to where his family was staying and he wrote out the entire piece from memory. Journeying to London, he gave this manuscript to the great scholar of music Sir Charles Burney. Burney published it. Burney was a member of the Church of England, so the ban wouldn’t have meant much to him. Eventually, news of this reached the ears of the Pope, who rather than excommunicating the young Mozart showered praise upon him for his musical gifts. However, the special Renaissance ornamentations were not in Burney’s publication and were not noted down until the 1840s. The ornamentation is part of what makes this piece special.
Here are the Tallis Scholars under the direction of Peter Phillips singing Allegri’s Miserere in the Basilica of Santa Maria Maggiore, one of the four major papal basilicas in the city of Rome.