When all of the Mardi Gras festivities are over, Christians begin the season of Lent, a 40 day period of observance leading up to Easter Sunday. The week leading up to Easter, called Holy Week, is of particular importance as Christians commemorate Christ's death and resurrection. Many composers have written music for Holy Week observances, but perhaps the most well-known of these pieces is the Miserere, mei deus by Renaissance composer Gregorio Allegri.
There is a popular story associated with this particular piece. In 1770, a 14-year old Mozart was visiting the Vatican and heard this piece performed by the choir of the Sistine Chapel. He only needed to hear it twice before transcribing the piece perfectly from memory, therefore providing us with the first "bootleg" copy of the work!