Requiem by Mozart, composed in 1791, was his last work. It became controversial because until our days we don't know up to what point it would be finished and dates from his death in the same year. It became controversial because to this day it is not known to what extent it would be finished at the time of his death in that year or would not have been completed by another person. Anyway, it is a paradoxical work because it is sad and serious unlike the child and almost jovial tone of the majority of his compositions but its beauty is extraordinary. I heard it today, the anniversary of his birth; it's a way of keeping him alive.

http://blog.uncovering.org/archives/uploads/2007/070127_mozart-requiem-lacrimosa.mp3