Wolfgang Amadeus Mozart's String Quartet No. 1 in G major, K. 80/73f, was completed in its original three-movement form on 15 March 1770 while touring in Lodi, Lombardy. Mozart was 14 at the time. The fourth movement was added later, possibly in 1773, when Mozart and his father visited Vienna.
In contrast to the Milanese Quartets, this quartet is in four movement form: