Wolfgang Amadeus Mozart (1756–1791) composed several masses and separate mass movements (such as Kyrie). Mozart composed most of his masses as a church musician in Salzburg:
Masses for regular Sundays or smaller feasts belonged to the missa brevis type. In the context of Mozart's masses brevis (short) applies primarily to the duration, i.e. the whole mass ceremony took no longer than three quarters of an hour. Instrumentation for such a missa brevis would usually be limited to violins, continuo (which included the organ), and trombones doubling the choral parts of alto, tenor and bass.
The generic name for longer masses was missa longa, for more solemn and festive occasions. Additional instruments include oboes, trumpets, timpani, and for some of them also French horns. Instead of treating each part of the mass liturgy in a continuous rendition of the text, there are repeats, fugues, and subdivisions in several movements with separate orchestral introductions.
Missa longa is usually synonymous with missa solemnis (solemn mass), however in Mozart's Salzburg (due to duration restrictions imposed by archbishop Colloredo), a hybrid brevis et solemnis (short and solemn) seems to have existed, short in duration, but nonetheless for the more festive occasions, for example including a more elaborate orchestration than the usual missa brevis.
After moving to Vienna Mozart started to compose the Great Mass in C minor, with a broad orchestration including violas and 12 wind instruments. In 1791, he started writing a Requiem mass, which was unfinished when he died and was first completed by his pupil Franz Xaver Süssmayr.
Most nicknames of the masses were later additions. The attribution to Mozart has been disputed for several masses, most of these spurious works first published by Vincent Novello from 1819.
