In January 1779 Mozart started his new position as court organist in Salzburg which entailed the composition of numerous sacred works. The autograph of his “Missa in C major” K. 317 – known as the “Coronation Mass” since the 19th century – was dated “li 23 marzo 1779”. This was noted in the composer’s hand at the beginning of the “Kyrie”. Possible dates of the premiere can be deduced from the dates of the Easter holidays in 1779 so it would have been either on 4 or 5 April.

Mozart probably w...