Every genius stands on the shoulders of giants. No less a composer than Mozart was once moved by a 12-minute composition written for the matins service on Holy Week that took place once a year in the Vatican. The name of that piece? Miserere mei, Deus (Have Mercy on Me, O God). The composer is Gregorio Allegri (1582-1652) who was also a Roman Catholic priest.

The story goes like this. During the Holy Week, the matins service in Rome’s Sistine Chapel would conclude with a performance of Miserere, a work Allegri originally wrote for Pope Urban VII for the exclusive use of the Holy Week service. It would be sung as 27 candles were gradually extinguished to leave one candle burning. As the singers soared off into the heights, the Pope himself would fall to his knees in front of the altar, dramatically ending the service.

The Pope loved the piece so much that he issued a decree forbidding the performance of the Miserere other than during Holy Week in the Sistine Chapel. No manuscripts were allowed to leave the Vatican, and anyone who tried to make a transcript risked excommunication.

In December 1768, the 14-year old Mozart set off on a tour of Europe with his father. One of the highlights was attending the Holy Week matins service at the Vatican to hear the Miserere, the only time in the year to listen to the beautiful piece. The boy was so taken by the performance that when he got back to his lodgings that evening, he sat down and wrote out the complete transcript of the 12-minute piece from memory. Then, he secretly returned for the Good Friday performance to check how accurate his transcript was. Needless to say, it required only minor corrections.

Mozart’s feat wasn’t so much one of memory as a reflection of his extraordinary ability to discern the underlying structure and logic of the composition. In particular, Mozart could pick out the inner symmetry of the piece in the same way a gifted mathematician is able to spot systematic patterns in apparently random numbers.

LISTEN

Here is the exceptionally beautiful and haunting Miserere written by Allegri for 2 choirs performed in St. Bartholomew the Great chapel, London. Listen to the two choirs alternate in phrases and then unite for a final resolution.