In 1780, when he composed his Vespers K339, Mozart was becoming increasingly frustrated with life in Salzburg, indeed, itching to escape from it. This is hardly surprising, given his fraught relationships with Archbishop Colloredo. They clearly detested one another. The Archbishop called Mozart, to his face, ‘ein Fetz’ – a nonentity; he also, for good liturgical reasons, put tight restrictions on the length and nature of Mozart’s settings, which must have been frustrating. Given that he also had a very controlling father, life in Salzburg must have been irksome.
1780 was also the year Emperor Joseph II ascended the Habsburg throne. To celebrate this, there was a ceremony held in March of the following year. The ceremony was held in Vienna, and Archbishop Colloredo was of course in attendance. He summoned Mozart to Vienna, housing him along with the other servants, which offended Mozart. What is more, Mozart had the opportunity to perform for the Emperor, for a fee equivalent to half his annual salary, and the Archbishop forbade this, since he wanted Mozart to play for his own concert. Mozart attempted to resign from the Archbishop’s services, but found himself summarily dismissed. The Archbishop’s deputy forcibly ejected him with, as Mozart put it, ‘a kick up the arse’.