Mozart’s Missa solemnis in C Major, K.337 is the last in a total of 18 complete masses he composed. Written even later, the Mass in C Minor, K.427 was never finished. Mozart wrote K.337 in 1780, during a very difficult period of his life.

In the 22 months of his second stay in Salzburg, Mozart’s compositions included two masses in C major (the Coronation Mass, K.317 and this Missa solemnis, K.337) as well as two vesper settings, K.321 and K.339. These four works are of particular beauty and maturity and in no way reflect Mozart’s inner struggle with his personal circumstances.

The name 'Missa solemnis' was assigned later to the Mass in C Major, K.337. Like other masses of that name it is festively scored, but because of its structure it might be classified as a missa brevis. It is perhaps because of its name that the Missa solemnis, K.337 has been rather unjustly overshadowed by the Coronation Mass that Mozart composed a year earlier.