The String Quintet No. 1 in B flat major, K. 174, was composed by Wolfgang Amadeus Mozart in December 1773. It is a "viola quintet" in that it is scored for string quartet and an extra viola (two violins, two violas and basso). Mozart composed this quintet a few months following the composition of the Viennese Quartets, K. 168-173. The average performance time of the four movements of the piece is 24 minutes.
