Sacred music occupies a large proportion in Mozart's works, but it is not his main achievement. Some people think that his best mass is the "Mass in C minor" (K.427), which was written on the occasion of his marriage in 1782. Although it was unfinished, it was composed out of his own inner needs. "Requiem", which he composed before his death, injects the author's deep feelings about the entire life, showing the exploitation, humiliation, cold treatment, poverty he suffered throughout his life as a citizen musician, as well as his unswerving pursuit of light and joy. and yearning. Mozart wrote most of the music, and his student F. X. Süssmeier completed it faithfully to his plan and style, and performed it in December 1793 under the title Count Walzeg.