this video is an edited short version of

Allegri's, Miserere
-this is the famous, "celebrated" recording of Allegri's Miserere that was 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 a Gramophone LP recording entitled 'Evensong for Ash Wednesday'(high Anglican) but the Miserere has subsequently been re-released on various compilation discs.
Notably, this setting is still sung in high-Anglican parishes during the imposition of ashes, on Ash Wednesday.
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Miserere, full name "Miserere mei, Deus" (Latin: "Have mercy on me, O God") by Italian composer Gregorio Allegri, 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, as part of the exclusive Tenebrae service on Wednesday and Friday of Holy Week. The service would start usually around 3AM, and during the ritual, candles would be extinguished, one by one, until one remained alight and hidden. Allegri composed his setting of the Miserere for the final act within the first lesson of the Tenebrae service. 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.[1] The setting that escaped from the Vatican is actually a conflation of verses set by Gregorio Allegri around 1638 and Tommaso Bai (also spelled "Baj"; 1650–1718) in 1714.