The early piano trio, the two piano concertos, the three piano sonatas and the late cello sonata op. 65 comprise Chopin's few contributions to sonata form, the principal form of the Classical era. Especially the two Piano Sonatas opp. 35 and 58 fully deserve their reputation as two of Chopin's most distinctive creations.
Chopin composed the Sonata in b minor op. 58 in 1844 at the country estate of George Sand in Nohant. This piece may be somewhat more conventional than the earlier b flat minor one, but Chopin shows in it that, contrary to the occasionally expressed view that strict (sonata) form was not to his liking, he most certainly mastered this genre, too, and was able to express himself as genuinely and intensely as in the smaller romantic character pieces.