Mozart had barely turned twelve when he composed and conducted his Missa solemnis in C minor, K.139, to inaugurate a new orphanage on Vienna’s Rennweg in 1768.
This astonishing early work adheres to the form of a Neapolitan cantata mass, in which the separate movements (“Gloria”, “Credo” etc.) are themselves made up of self-contained choruses, ariosos and ensembles.
This frequently heard Mass is characterized by a sharp contrast between its cheerful underlying C major mood and gloomy dramatic passages in the minor mode.