This beautiful piece of music Miserere mei is Psalm 51, first set to music by Italian Gregorio Allegri around 1630.
Music as sublime as this really is timeless..
There is an interesting reflection on background to its performance from here
and the comments section is also worth reading.
I first came across this piece of music many years ago when I was looking for some music to play as part of a Lenten retreat for Young Adults and I bought a record without having any idea what the music would sound like- I just liked the cover of the LP ( yes, that long ago!)
When I heard this piece all those years ago I was deeply moved by it.
By chance I came across a link that led me to this version and it was not until today that I discovered it was Psalm 51 and saw the English translation and nor did I know the background to it.
I'm still not sure if any of that really matters - for me the music alone is pure prayer and if you can spare ten minutes to switch off the lights, lay back and close your eyes and just listen to the music it is beautiful...