On September 23, 1777, Mozart left his native Salzburg bound for Paris by way of Munich, Augsburg, and Mannheim. Mozart and his ever-ambitious father, Leopold, hoped to secure a position for the young composer away from Salzburg and the court of their current employer, Archbishop Colloredo. Leopold remained at home under Colloredo's employ and his wife, Anna Maria, accompanied their son on the trip.
Leopold would not see his wife again. Anna Maria died suddenly of an undiagnosed illness in Paris in July 1778. Some have connected the sonata K. 304 of the same year to Anna Maria's death, but this tragic event and the piece are unrelated. K. 304 is the only one of Mozart's sonatas for violin and piano written in a minor key and conveys a deep pathos. But work on the sonata was begun in Mannheim in the spring of 1778 before the Mozarts traveled to Paris, and Mozart finished K. 304 before Anna Maria's sudden demise.