This year,Wednesday 2nd March is the start of Lent for Christians. It is a time when Christians are preparing for Easter. They remember how Jesus spent 40 days fasting in the desert. Christians will often give something up during this time. Lent starts on Ash Wednesday (the day after Shrove Tuesday, often called 'Pancake day'). This piece of music is sung in some churches during the Ash Wednesday service. This is a service when Palm crossed are burned and turned to ash. The ash is then used to draw a cross on the forehead of each person attending. It is a sombre and thoughtful service, and this music reflects that.
This piece is called Miserere mei, Deus (Latin for "Have mercy on me, O God"). It is Psalm 51 set to music by Italian composer Gregorio Allegri. It was composed in the 1630s, for the exclusive use of the Sistine Chapel.
It was forbidden to write the notes down and was only allowed to be performed at particular services. In the late 1700s, the famous composer Mozart visited Rome and heard it performed. He was only 14 at the time. He heard it once and then went home and wrote all of the notes out by memory. When everybody found out, he was summoned back to Rome by the Pope who told him he was a musical genius and gave him an award. There is no longer a ban on the music and is now a very popular a cappella (no instruments) choral work performed.