Miserere Mei, Deus (meaning Have mercy on me, O lord) which is also known as Miserere in short is a renaissance polyphony representation of psalm 51 composed by Gregorio Allegri and the greatest thing about this historical work is that it was only performed in Sistine Chapel (at Vatican City), specifically only on Holy Wednesday and Good Friday. Funny thing was that there were "copyright" issues in the past; writing the score down or performing it anywhere else other than the Sistine Chapel was punishable by excommunication, which is equivalent to being banished from the church. Thank god for the little musical genius Mozart who written the entire score down from memory after hearing it being performed at Sistine Chapel, if not this chant would forever be trapped in the mystery of Sistine Chapel.
Being a vocally demanding and intensive piece, due to extremely high range required for Sopranos (Soprano C is the highest note) and the fact that is no mere SATB arrangement but a 9-part arrangement (Cantus I, Cantus II, Secundus I, Secundus II, Altus I, Altus II, Tenor, Bassus I, Bassus II) makes it a challenging choral work, which challenges even the best of choirs around. There are no accompaniment to mask anything and the slightest of any musical error would be highly visible.
I decided to use a professional renaissance-dedicated vocal ensemble, The Tallis Scholars who performed this musical piece since it has one of the best blend around (it's professional anyway) and just hearing the Soprano C makes me go "wow"!