(Piano reduction of the two piano version containing the two solo piano parts plus a third part being the orchestral reduction) Commissioned by the Countess Antonia Lodron and written in Salzburg in February 1776 for performance by the Countess and her two daughters, Mozart later re-arranged the piece for two pianos. This later version was performed by Mozart and his sister, Nannerl, in Salzburg on 3rd September 1780.