The Missa K.257 bears the non-authentic dating 1776 and was presumably composed at the end of 1776 or in the first half of 1777. Like K.262 (246a), it is designated in Leopold Mozart’s handwriting as a Missa longa on the coverpage of an early composite manuscript containing the five masses in C major. K.257 is listed there as the last work. The designation “Missa longa” was intended to point out that this was an extensive, full-scale mass. Normally,it would have been called a Missa solemnis but Mozart, for unknown reasons, did not make use of this customary nomenclature.
The name “Credo Mass” is taken from the acclamations of “Credo” that constantly interruptthelike-named movement. The Mass is remarkable for its density of invention within the narrowest of confines. Further, its instrumental accompaniment has an almost chamber-music quality that emerges time and again into almostsymphonic proportions.
| Arrangement | Mixed Choir |
| Genres | Classical |
| Format | Parts |
| Media | Sheet Music |
| Publisher | Bärenreiter-Verlag |
| Contributors | Amadeus Mozart, Wolfgang(Composer) Senn, Walter(Artist) |
| ISMN | 9790006457588 |