Organ Sonatas, Op.65
One of his primary works for organ, Mendelssohn's Op. 65 Organ Sonatas were composed in 1845. In 1844, Mendelssohn was commissioned to begin a set of voluntaries for the general English populance. The definition of voluntary at the time was fairly ambiguous. It was understood by Mendelssohn that it was meant to be organ music set in a collection without an exact form. The point was for the music to be adaptable and appropriate in a variety of situations and circumstances. In writing these "voluntaries" Mendelssohn drew from the inspiration of Bach, having the year before performed Bach's preludes, fugues, and Orgelbüchlein in concert. The Six Organ Sonatas were published by Coventry & Hollier in 1845, a publishing house dedicated to promoting Bach and supporting Mendelssohn's efforts. It may be of worthy of note that Mendelssohn constructed a number of his sonatas from several previously composed but dissociated and unpublished movements. Whatever their origin, they are undoubtedly by Mendelssohn's hand and have been widely studied by organists since their publication.
Organ Sonata Op.65 No.4 in B flat major
Organ Sonata Op.65 No.6 in D minor