Miserere mei, Deus ‘Have mercy on me, O God’ by Gregorio Allegri Italian composer Gregorio Allegri most likely completed this adaptation of Psalm 51 in the 1630’s. The work was for the exclusive use of the Sistine Chapel choir during the Holy Week. It is an a cappella for two choirs with either four or five voices depending on the adaptation. The work was closely guarded by the church, with only three approved copes of the work being distributed until the 18th century. In 1770 the fourteen-year-old Wolfgang Amadeus Mozart heard this work during the Wednesday Service. According to family letters, Mozart copied the music to manuscript correctly, and was later acknowledged by Pope Clement XIV for this musical ability and given the Order of the Golden Spur.