The Piano Sonata in C major 613 is an unfinished piano sonata written by Franz Schubert in April 1818.
Only a fragment exists, ending after the development with an implied cadence in E major.
According to Martino Tirimo, Schubert's Adagio in E major, D. 612 is most likely the middle movement of this sonata.
Lacking a tempo indication, this movement is in the style of a siciliana. It is incomplete, and ends at what is presumably the end of the development.