Few composers have generated as many anecdotes, stories, (some of them outright distortions) as Johann Sebastian Bach. The blame lies not only with the nineteenth century, when efforts to turn Bach into an especially “German” composer (and a staunch “Lutheran” of course) reached their first peaks. Don’t blame Johann Nikolaus Forkel, Über Johann Sebastian Bachs Leben, Kunst und Kunstwerke (1802), for this. He rendered important services to our knowledge of Bach, and transmitted legends. Responsibility also lies with Johann Sebastian’s second eldest son, Carl Philipp Emanuel. He was inclined, at times, to polish his father’s image with an eye to effective promotion.
C. P. E. Bach wrote beneath the unfinished fugue, which was first printed in 1751:
„Über dieser Fuge, wo der Name BACH im Contrasubject angebracht worden, ist der Verfasser gestorben.“
(Over this fugue, where the name BACH has been introduced into the countersubject, the composer died.)
The verso of the title page of the Printed Edition (1751) further states:
„Der selige Herr Verfasser dieses Werkes wurde durch seine Augenkrankheit und dem kurz darauf erfolgten Tod ausser Stande gesetzet, die letzte Fuge, wo er sich bey anbringung des dritten Satzes namentlich zu erkennen giebet, zu Ende zu bringen; man hat dahero die Freunde seiner Muse durch Mittheilung des am Ende beygefügten vierstimmig ausgearbeiteten Kirchenchorals, den der selige Mann in seiner Blindheit einem seiner Freunde aus dem Stegreif in die Feder dictiert hat, schadlos halten wollen.“
(The late author of this work was prevented, by his eye disease and the death that followed shortly thereafter, from completing the final fugue, in which, upon the introduction of the third subject, he reveals himself by name; therefore, in order to compensate the friends of his Muse, one has wished to provide the four-part church chorale appended at the end, which the late man, in his blindness, dictated extemporaneously to one of his friends for writing down.)
Today we know that in his final years Bach was occupied with several projects, among them the B minor Mass and the Eighteen Leipzig Chorales. The Art of Fugue, whose first version dates back to the early 1740s, had already been set aside for some time. In other words, Death did not wrench the pen from the hand of genius while he was at work; the manuscript had already gathered a little dust by the time Bach died.
Hypothesis: Perhaps Bach was also working on the Fugues, in order to complete them, and get them published/printed The Art of Fugue, why not: Clavierübung V, why not: submitting it as his final contribution before retirement to the Correspondierende Societät der musicalischen Wissenschaften (Mizler’s Society), to which, among others, Telemann, Handel, and Leopold Mozart belonged.
The work in question is the setting of the hymn Wenn wir in höchsten Nöten sein (BWV 668), belonging to the Eighteen Leipzig Chorales.
However, Bach had already assembled this collection of revised earlier works between 1739 and 1742. During his final years he merely introduced some modifications, mostly corrective in character, and placed above the piece the title line of another text long and frequently sung to the same melody: Vor deinen Thron tret ich hiermit (“Before Thy throne I now appear”), intending to incorporate it into the renewed revision of the Eighteen Leipzig Chorales, with which he was then occupied.
The resulting version is catalogued as BWV 668a, but it is not identical with the composition that the family placed at the end of The Art of Fugue. That appendix is simply the slightly older version, BWV 668, as it already appeared in the Leipzig Chorales of 1739–42. Confusion among the various versions seems to have begun almost immediately after Bach’s death.
The text on the title page of The Art of Fugue therefore amounts to little more than effective marketing. Bach himself almost certainly never intended to establish such a connection, since the chorale setting is a stylistically alien appendix. There happened to be an empty page left in the printed edition, and under this somewhat sentimental pretext it was filled with precisely this organ chorale setting.