For all the partying Mozart seems to have done, he definitely had his prudish side when it came to the company he kept. Just ask Mozart's colleague Antonio Brunetti.
In 1775, at the time Mozart wrote his First Violin Concerto, K. 207, he was 19 years old and serving as concertmaster in the orchestra at the court of Salzburg Archbishop Hieronymous Colloredo. Brunetti was a violinist in the same orchestra, and Mozart came to know him as a capable player.
By 1777 Mozart had composed some violin works for Brunetti and, on Brunetti’s recommendation, had even composed an alternate final movement to his First Violin Concerto.
In 1778, Brunetti married Maria Judith Lipps in a shotgun wedding, after the birth of their child earlier that year. Such events were considered scandalous in Mozart's day, and in his correspondence Mozart doesn't mince words about Brunetti.
In a letter of July 9, 1778, Mozart wrote from Paris to his father, calling Brunetti "a thoroughly ill-bred fellow," adding later that if Brunetti were to be dismissed from his job, Mozart would like to recommend to the Archbishop a friend to replace him. (Letters of Mozart and His Family, trans. Emily Anderson).
The big shake-off came a few years later. On March 24, 1781, Mozart wrote his father, "The other day when we were to go to Prince Galitzin's Brunetti said to me in his usual polite manner: 'You must be here at seven o’clock this evening, so that we may go together to Prince Galitzin's. [The prince's valet] will take us there.' I replied: 'All right. But if I'm not here at seven o'clock sharp, just go ahead. You need not wait for me. I know where he lives and I will be sure to be there.' I went there alone on purpose, because I really feel ashamed to go anywhere with them."
The following month, Brunetti quit his job. On April 11 Mozart wrote his father, "Praise be to God that at last that coarse and dirty Brunetti has left, who is a disgrace to his master and to the whole orchestra."
Even so, Mozart continued to write violin solo works for Brunetti, and to perform them with him in public.
