Composed around the previously written Funeral March, Sonata in B-flat minor, Op. 35 and, considered by some to be Chopin's greatest and most profound work, the Sonata in B minor, Op. 58 are works from the period of synthesis, masterly technique and particularly intense expression. Preceding them is the Sonata in C minor, Op. 4, sometimes called the "school" is a testament of Chopin's path to the sonata.