Mozart wrote his Vesperae solennes de confessore K.339 at the age of 24, in the aftermath of discovering that the world was not quite ready for him yet.
He had essentially quit his musical job working for Count Colloredo in his hometown, had almost gotten his father fired in the process, and left for Paris seeking his fortune with his Mother as chaperon. He stopped in Mannheim along the way, and immediately fell in love with a soprano named Aloysia Weber. Accordingly, using post-adolescent logic, he wasted time and resources, and pressed the patience of his parents hoping to stay there.
Fortune finally persuaded him to move on to Paris, where he made all attempts to impress nobility and to find musical employment. Late in June his Mother developed a high fever, and died on July 3. This single event shook and changed him, in the midst of the realization that he would never receive a substantial offer for musical employment in Paris. He left for home embarrassed, depressed and bewildered.
On his way back, he stopped for consolation from Aloysia Weber, only to discover that she had forgotten him, and was already seeing someone else. Two years later, he married Aloysia’s sister, Constanze. His father had managed to plead with the Count, begging forgiveness for his son and eventually getting him his job back. It was in the year following these events that the Vesperae was created in Salzburg, for the Count.
The Vespers were a traditional part of the Roman Catholic liturgy, within the Divine Offices; which were services designed to take place from dawn through dusk. The Vespers were the seventh of eight offices comprising this worship, and were celebrated at sunset. It was the only office for which concerted music was allowed by the Church. The Vespers consisted of five psalm texts (#110, 111, 112, 113 and 117), a hymn, and it culminated with the Magnificat (which is the Canticle of the Virgin Mary from Luke 1:46-55).
Other composers set the Vespers, or adapted its texts in their own way both before and after Mozart, including Monteverdi, Alessandro Scarlatti, Tchaikovsky, and Rachmaninoff. Mozart set the complete Vespers twice (K.321 and K.339) both of which are in C major, and both leave out the hymn to create a six movement design. Six years earlier he had also set the Dixit and Magnificat texts in C major K.193.
Known during his lifetime primarily as an opera composer, the influence of operatic style was often present in non-operatic works by Mozart. It is fascinating to hear how Mozart infuses a sacred text with the spirit of opera, while still maintaining the strict and proper religious spirit of the times demanded by Count Colloredo. The operatic style is often introduced with music given to soloists. In the Dixit Dominus, in the midst of the contrasts, organizational complexity and juxtaposed styles, the soloists introduce an operatic style briefly and subtly in the final section, where they preface the re-presentation of music heard earlier in the movement with music and style unique to themselves. The middle section of the Confitebor is like an operatic scene, and is given entirely to soloists. In the Beatus Vir and the Magnificat, soloists alternate with the choir. Soloists, and operatic qualities are lacking only in the J.S. Bach influenced Laudate Pueri, which in its austerity helps to prepare the jewel of the collection, Laudate Dominum, set as an operatic aria for the soprano soloist.