It has been awhile since we have spoken about sacred music and one video I have frequently shared elsewhere is this recording of Mozart's famed Requiem setting, but as executed within its proper context: the traditional Requiem Mass. More frequently Mozart's great work is executed as a choral performance, very often in a church setting, but seldom is it actually heard and seen within its appropriate liturgical context, intermingled with the proper chants of the Mass and the compelling ceremonial of the ancient Roman liturgy.
The following recording comes from Poland, and was a requiem, for Mozart himself I believe, celebrated by Fr. Bernward Deneke of the Priestly Fraternity of St. Peter.