Missa in C Major K. 258

Although the composition date is unclear, Mozart's 'Missa in C major' K. 258 was most probably written around 1775/76. This mass was composed in 'brevis' form and was named as such on the cover of the collected volume for the incipit. As Mozart supplemented the customary trio instrumentation with further instrumental parts, this work could also be of the 'brevis et solemnis' genre. Mozart added two oboes to the orchestral parts – the performance parts were written in Mozart's hand and supplement the primary manuscript. However, these two oboe parts never seem to have reached a copyist, as up to the present day, no copy of the work including these parts has come to light. The editor Walter Senn has included the oboe parts in this Urtext edition. Corrections and additions made by the editor are marked typographically in the musical text.