Look for Part I. Regardez pour la 1e partie. Miserere by Italian composer Gregorio Allegri (also called "Miserere mei, Deus" - English "Have mercy on me, O God") is a setting of Psalm 51 (50) composed during the reign of Pope Urban VIII, probably during the 1630s, for use in the Sistine Chapel during matins on Wednesday and Friday of Holy Week. It was the last of twelve falsobordone Miserere settings composed and chanted at the service since 1514 and the most popular: at some point, it became forbidden to transcribe the music and it was only allowed to be performed at those particular services, adding to the mystery surrounding it. Writing it down or performing it elsewhere was punishable by excommunication. The setting that escaped from the Vatican is actually a conflation of verses set by Gregorio Allegri around 1638 and Tommaso Bai (1650 - 1718, also spelled "Baj") in 1714. The Miserere is written for two choirs, one of five and one of four voices. One of the choirs sings a simple version of the original Miserere chant; the other, spatially separated, sings an ornamented "commentary" on this. Many have cited this work as an example of the stile antico or prima pratica. However, its constant use of the dominant seventh chord and its emphasis on polychoral techniques certainly put it out of the range of prima pratica. A more accurate comparison would be to the works of Giovanni Gabrieli. Mozart was summoned to Rome by the Pope, only instead of excommunicating the boy, the Pope showered praises on him for his feat of musical genius. Burney’s edition did not include the ornamentation or "abbellimenti" that made the work famous. The original ornamentations were Renaissance techniques that preceded the composition itself, and it was these techniques that were closely guarded by the Vatican. Few written sources (not even Burney's) showed the ornamentation, and it was this that created the legend of the work's mystery. However, the Roman priest Pietro Alfieri published in 1840 an edition with the intent of preserving the performance practice of the Sistine choir in the Allegri and Bai compositions, including ornamentation. The Miserere is one of the most often-recorded examples of late Renaissance music. A famous, "celebrated" recording of Allegri's Miserere was that made in March 1963 by the Choir of King's College, Cambridge, conducted by Sir David Willcocks, which featured the then-treble Roy Goodman. This recording of the Miserere was originally part of an LP recording entitled 'Evensong for Ash Wednesday'[2] but the Miserere has subsequently been re-released on various compilation discs. (From Wikipedia. Letter from Leopold Mozart to his wife [Sent from Rome, dated April 14, 1770. Only parts of the letter relevant to the transcription episode are given here.] We arrived here safely on the 11th at noon. I could have been more easily persuaded to return to Salzburg than to proceed to Rome, for we had to travel for five days from Florence to Rome in the most horrible rain and cold wind. I am told here that they have had constant rain for four months and indeed we had a taste of it, as we went on Wednesday and Thursday in fine weather to Saint Peter's and to the Sistine Chapel to hear the Miserere during the mass, and on our way home were surprised by such a frightful downpour that our cloaks have never yet been so drenched as they then were... You have often heard of the famous Miserere in Rome, which is so greatly prized that the performers in the chapel are forbidden on pain of excommunication to take away a single part of it, to copy it or to give it to anyone. But we have it already. Wolfgang has written it down and we would have sent it to Salzburg in this letter, if it were not necessary for us to be there to perform it. But the manner of performance contributes more to its effect than the composition itself. So we shall bring it home with us. Moreover, as it is one of the secrets of Rome, we do not wish to let it fall into other hands, ut non incurramus mediate vel immediate in censuram Ecclesiae. --translation by Emily Anderson, in her The Letters of Mozart and his Family; London: Macmillan, 1938.