Instrumental Duet Guitar,Instrumental Duet - Digital Download SKU: A0.493767 Composed by Wolfgang Amadeus Mozart. Arranged by Pedro Nunes. Classical. Score and parts. 9 pages. Published by Pedro Nunes (A0.493767). Wolfgang Amadeus Mozart's String Duo No. 1 in G major for violin and viola, K. 423, the first of the two Mozart wrote. It was written in the summer of 1783. Here I present the first movement arranged for two guitars. A difficult duet which requires a lot of technique and patience.