Wolfgang Mozart died on December 5, 1791, leaving behind an unfinished Requiem Mass, commissioned anonymously by Count Franz von Walsegg, a 28-year-old Austrian nobleman who had the ignoble habit of passing off works he commissioned as his own. The Requiem was intended to be a memorial to the Count’s 20-year-old wife, Anna, who had died earlier that year.

Mozart’s wife Constanza arranged for some of Mozart’s pupils to complete the unfinished score, and eventually delivered it to Count Walsegg in order to receive the full commission fee promised her husband.

But just five days after Mozart’s death in 1791, the portions of the Requiem that Mozart himself had completed were sung at a memorial service organized by his friend and collaborator Emanuel Schikaneder.

Schikaneder was the librettist for Mozart’s opera “The Magic Flute,” and ran his own opera house at the Theater auf der Wieden in a Viennese suburb. It was there that Mozart’s “Magic Flute” had premiered, and it was Schikaneder’s musicians who performed parts of Mozart’s Requiem for the first time on today’s date in 1791, at St. Michael’s Church in the center of Vienna.

Lili Kraus, a 20th century Hungarian concert pianist closely associated with Mozart’s music, said of his Requiem Mass, “There is no feeling—human or cosmic, no depth, no height the human spirit can reach—that is not contained in his music.”