This is the Romanza from the Grande Sonate in A for guitar and violin by Niccolo Paganini.
The story around this Sonata originates from the cooperation of Paganini and Luigi Legnani (1790 – 1877). They toured Europe together, Paganini as a soloist on violin, Legnani as accompanist on the guitar. If you listen to Paganini’s “ordinary” Sonatas for violin and guitar, it becomes quite obvious who literally plays the first fiddle. A brilliant and virtuoso role for the soloist, a moderate role for the accompanist.
Apparently Legnani did not like this, because he suggested to change instruments for one piece. For this purpose, Paganini composed the well-known Grande Sonate in A for guitar and violin.
Doing so, he fooled his duo partner, because in this composition all virtuosity was in the guitar part and the violin got a secondary role next to none at all. That is the reason why this Sonata is often played as a guitar solo. The piece appeared to be one of the most difficult pieces from guitar literature, a clear sign that Paganini was quite skilful on the guitar!
The Romanza starts easily and quietly. Soon, however, the complexity starts in “the small notes”, the written variations and cadenzas.
While scoring this setting, I have tried to combine the guitar and violin parts. Particularly in the first section this gives more body to the chords. In the fast runs, however, I left the violin accompaniment out, I guessed that the guitar part alone is more than sufficient to keep you busy!