This alleged
Mozart Missa solemnis in C major, officially designated KV C1.20 in the Köchel Catalog, is billed below Bavarian composer Simon Mayr's unquestionably authentic Te Deum in D major (1805), it is actually the main course on this Naxos disc featuring the
Ingolstadt Georgian Chamber Orchestra and the
Simon Mayr Choir under
Franz Hauk with a group of solo singers. The reason for combining the supposed
Mozart Te Deum with the Mayr is that the best of several copies of this work found throughout Europe was made by him. Mayr's copy also bears a date of 1802, which consolidates that the work existed before then, and there are a couple of movements -- the opening Kyrie and the Qui tollis peccata mundi -- that contain enough of a genuine Mozartian flavor that it suggests this might have been a work of Leopold Mozart's that his son slightly touched up. However, there is clearly an element of pastiche to the composition of this Missa solemnis, in which case we might never know who really wrote it; there are movements that suit neither
Mozart particularly well. If you are the kind of listener who likes to play the guessing games of tricky attributions or are strongly interested in
Mozart works that are not likely his, then on that basis alone Naxos'
Mayr: Te Deum -- Mozart: Missa solemnis may well interest you.