1770 A.D. Rome. The Sistine Chapel. It is Wednesday in Holy Week. Several hours before dawn, worshippers assemble in the famous chapel, adorned with the legendary frescoes of Michelangelo, for the Tenebrae service. Among them are an Austrian gentleman (the unique nature of this particular service draws visitors from all over Europe) and his teenage son. The service itself consists of a ritual extinguishing of candles, accompanied by readings, prayers, and musical settings of appointed texts. Most notable among these latter is a setting of Psalm 51 (Miserere mei, Deus - Have mercy upon me, O God) composed a century-and-a-half prior by Gregorio Allegri. An aura of mystique surrounds this musical work, reported to be an exceptionally beautiful and intricately polyphonic interplay between two choirs, totaling nine separate voices. So highly is it prized by the Roman Church, that transcribing or performing the music elsewhere is forbidden under the threat of excommunication.
The service proceeds. The glorious Miserere is sung, to the enraptured delight of all present, especially those guests who are hearing it for the first time. As the service concludes, a final lit candle is briefly hidden away under the altar and then reproduced, providing just enough light for the worshippers to find the exit. As they file out silently, the Austrian gentleman looks down with upraised eyebrows toward his son. In the dim light, the son returns his father's questioning glance with a precocious grin and a wink of the eye. Later in the day, back in their quarters elsewhere in the city, the boy takes pen to paper and transcribes, from memory, Allegri’s Miserere from beginning to end. The pair return again to the chapel for the Good Friday Tenebrae Service, the only other time in the whole year when the piece is performed. This second hearing furnishes opportunity for the boy to make the few additional mental notes he needs in order to perfect the transcription.
The father and son are, of course, Leopold and Wolfgang Amadeus Mozart, who was fourteen at the time. During their subsequent travels, they shared the transcription with a British historian, who took a copy home with him to London and published it the following year. When it became known who was responsible, the Pope, rather than excommunicating Mozart, instead heaped laudations upon the boy for his impish genius. The ban was lifted, and today Allegri’s Miserere is among the most highly regarded of a cappella choral works.