While visiting Constanze, pregnent with their sixth child, at the spa south of Vienna (Baden bei Wien), Mozart composed his motet Ave Verum Corpus (K. 618). Composed for his friend, Anton Stoll, who was the music director of St. Stephens, for the Feast of Corpus Christi, it is a sublime forty-six measures in length and was originally scored for SATB choir, strings, and organ. The date notated on the score (June 17, 1791) was just six months before his death and three months before the premiere of his final opera, The Magic Flute.
 
For this arrangement for eleven piece brass ensemble, Michael Allen has transposed the work from its original key of D major to E flat major and made other small adjustments to phrasing and dynamics.