Wolfgang Amadeus Mozart's Mass in C Minor, K427, is a religious musical work for chorus and orchestra. It is considered such a great musical work that it is called the 'Great Mass'.

Why did Mozart write the Mass?

Unlike many of Mozart's other pieces of music (including his Requiem) the mass was not commissioned. Mozart wrote it purely for his own pleasure - in fact, he probably spent time writing the mass when he should have been working on his boring paid commissions. Clues from letters have led many people to believe that Mozart wrote the mass partially in thanksgiving to God, possibly because of good events that had recently occurred in his life. These events included his marriage to Constanze Weber, the birth of their first child, and Constanze's recovery from illness. He could also have been trying to prove something to his father.

About the History and Music of the Mass

Like all other masses, this one contains the following sections in order: Kyrie eleison, Gloria in excelsis Deo, Credo in unum Deum, Sanctus and Benedictus. However the final part, Agnus Dei, is missing, and the Credo is incomplete. The texts for these sections are the same in all masses (although performances at certain times of the year may see some parts omitted).

The mass is thought to have been written in 1782 - 83, and was first performed on the 26 October, 1783 (Mozart's sister Nannerl mentioned in her diary that a half-finished mass by her brother was performed; Constanze was apparently the solo soprano singer). It is thought that sections from other masses were performed alongside Mozart's to fill in the missing bits.

Many parts of Mozart's C Minor Mass are similar to his Requiem - you could call the mass a sort of forerunner to the Requiem¹. The first section of the mass, Kyrie, starts softly with strings. Other parts of the orchestra join in and there is a small crescendo before the chorus enters. Mozart tends to have timpani and brass playing on the same beats, a technique he also used in the Confutatis section of his Requiem (the Kyrie, however, is nowhere near as furious as the Confutatis). The Gloria section begins in C Major and sounds quite jolly. However, a portion of the Gloria called Gratias, sounds extremely sad. The Qui Tollis sounds like some parts of the Requiem, with similar string techniques used. The mass ends with the Benedictus in A Minor. It is possible that Mozart was planning to write the Agnus Dei in C Minor. At the time of writing the mass, Mozart is said to have been interested in the music of Handel and Bach. Parts of the mass mirror their styles.

In 1785 Mozart re-used some of the material from the mass in his cantata K469, Davidde penitente.

The general scoring for the mass is for pairs of oboes, bassoons, horns and trumpets, plus three trombones, strings, timpani and an organ continuo. There is a four-part (soprano, alto, tenor and bass) chorus, but there are two soprano soloists, one tenor, and one bass (no alto). The scoring varies throughout the piece. The Domine section of the Gloria, for example, uses only strings and soprano soloists.

Even though Mozart never really finished the mass, it has the title of 'Great Mass' as it is considered one of his greatest works for orchestra and choir, along with his Requiem (incidentally, he did not finish that either). The piece is so popular it is still often performed today.