Mozart’s father never liked his son’s engagement with Constanze Weber, and he only approved it when the wedding was already inevitable.
It is not known why Mozart, after leaving Salzburg and moving to Vienna with Constanze, wrote the Great Mass in C minor, but everything seems to indicate that it was in response to a promise that Mozart made himself: he would premiere a new mass in C minor in Salzburg if he could get Constanze as a wife and officially introduce her to her father.
Finally, Mozart achieved his purpose. He returned to Salzburg and premiered the mass in the church of Sant Pere on October 23, 1783, with Constanze singing one of the solo soprano roles and in the presence of his father Leopold Mozart and Nannerl, his beloved sister.
According to Maynard Solomon, the composer’s biographer, this mass of sublime beauty represented an offering of absolute love from Mozart to his loved Constanze.
Mozart and Constanze stayed together until the composer’s death in 1791. Together they had six children, only two of whom survived childhood. Constanze died in 1842 at the age of eighty, after completing the first biography of the genius from Salzburg.