In Vienna in the 1780s, the string quintet genre experienced a real boom. This was a circumstance that Mozart was well placed to take advantage of, as he was used to the rich middle part movement with two violas in chamber and orchestral music from Salzburg. So it is no wonder that the first viola in his quintets is entrusted with solo tasks. 

The virtuosity of the fifth voice is exemplary in the quintet in C major. Mozart himself has performed it repeatedly in the salons of his patrons. In some of the memorable performances, none other than Mozart and Haydn shared the viola parts, which elicited the almost overwhelming abundance of sound combinations from the piece.