Original autograph manuscript in the hand of Mozart.

Wolfgang Amadeus's father Leopold’s label on the front of this music manuscript reads ‘composto nel Mese di Marzo 1766’ - composed in the month of March, 1766. Recent scholars, however, assign the work to March 1767, when the family was in Salzburg and Mozart was 11. The first act of an oratorio, with words by Ignas Weiser, and the second and third acts, now lost, composed by Michael Haydn and Anton Adlgasser, it was first performed in the Archbishop of Salzburg’s Rittersaal on 12 March and repeated on 2 April 1767. The allegorical work is scored for five voices, two tenors and three sopranos, with various combinations of wood-wind, strings and brass. The arias were composed first, since each starts on a recto, and the blank pages all follow the subsequent recitatives.

It is said that the Archbishop, sceptical of Mozart’s genius, incarcerated him with a text to set to music. K.35, once thought to be the product, is too complex with too many corrections by Leopold, and Grabmusick K.42 is now preferred.