Not an original composition: in Salzburg in 1767 the eleven-year-old Mozart arranged movements from keyboard sonatas by other composers — Hermann Friedrich Raupach and Leontzi Honauer among them — adding orchestral parts to make three-movement concertos. K. 37 is the first of four such exercises, K. 37 and 39–41, and Leopold Mozart's hand in the manuscripts suggests close supervision. They were long counted as Mozart's own. 175 of 1773.