By Aaron GreenJune 29, 2018 … Gregorio Allegri composed Miserere mei, Deus in the 1630s, during the papacy of Pope Urban VIII … [Urban] loved the piece so much that he forbade it to be performed elsewhere outside of the Sistine Chapel. For over 100 years, Allegri's piece was performed there exclusively. Anyone caught with a transcription of the piece outside of the chapel could be immediately excommunicated from the Church. In 1770, a 14-year-old Wolfgang Amadeus Mozart was present at one of the performances while touring Italy with his father. After hearing the piece, Mozart transcribed the work entirely from memory and even made corrections. He attended one more performance to make his final adjustments. The following year, after meeting with music historian and biographer, Dr. Charles Burney, Mozart gave him the sheet music. Burney took the score to London and published it, which resulted in the papacy lifting its ban.