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Week 4: Cantus Firmus

Like canons and inventions, chorale preludes are polyphonic elaborations of preexisting material called the cantus firmus. The cantus firmus is a formal object, typically AAB, that lends its form to derivative works which employ contrapuntal means to fragment, mirror, echo, and re texture the cantus firmus in other voices. While they can be subsumed under the techniques of chorale prelude, depending upon instrumentation and the manner in which they are elaborated, these derivative works are also called: chorale motet, chorale fantasia, chorale variations, chorale partita, chorale fugue, or chorale cantata.

The poplar's trunk (detail to right) unites the ground to leafy canopy and sky above. The tree is analogous to a preexisting melody stitching the elements of a composition together. In music, we call this melody a cantus firmus. Because Bach used the chorale, his cantus firmus works for organ are called chorale preludes. But, as a procedure, the techniques of chorale prelude apply to any polyphonic elaboration of a preexisting melody.

The cantus firmus has its own form--some melodies are binary (AB) while others are ternary (ABA). Monet's detail to the right might be considered a binary, with sky at the top being part "A" and leaves at the bottom being part "B." The Lutheran chorale typically subscribes to an extended binary in which section "A" (called the Stollen) is repeated and followed by a section "B" (the Abgesang) which is not repeated. This AAB schematic is known as German bar form.

Chorale preludes state the cantus firmus in one or more voices with remaining voices providing suitable counterpoint. Naturally, the resulting prelude replicates the form of the cantus firmus upon which its elaborations hang. So, if its cantus firmus subscribes to bar form, then the chorale prelude, too, will be in bar form. The cantus firmus is the glue, then, that lends form to the prelude and keeps its parts from falling apart. The following links will introduce you to various ways the cantus firmus can appear. As you study them, keep an inventory of which chorales (and their preludes) are in bar form and which are not.

Musical examples in this unit can be played from the Cantus Firmus disk. Please check this disk out and insert it into the ROM drive at this time. Next...

Reading:
  1. Stein "Structure & Style" pp. 147-148
  2. Stein Anthology "Now Thank We All Our God" p. 6
Listening: | Stop CD |
  1. Excerpt from Motet BWV 225 Singet dem Herrn ein neues Lied (cantus firmus with interpolations between phrases)
  2. First mvt. Cantata BWV 80 Ein feste Burg (cantus firmus with fugue)
  3. First mvt. Cantata BWV 79 Gott, der Herr, ist Sonn' und Schild (cantus firmus with ritornello)
  4. Last mvt. Cantata BWV 147 Herz und Mund und Tat und Leben (cantus firmus with ritornello)
  5. First mvt. Cantata BWV 61 Nun Komm der Heiden Heiland (distributed cantus firmus)
  6. Canonic Variations on Vom Himmel hoch (cantus firmus IN canon and WITH canon)
  7. Liebster Jesu Prelude (cantus firmus in canon)
  8. O Mensch bewein Prelude (decorated cantus firmus)
  9. Vater Unser Prelude (cantus firmus in Long Notes)
Quiz No. 1: If you started reading at the top of this page, followed all the "Next..." links, and have arrived back here, then you should be ready to take the cantus firmus quiz. This quiz is due at the beginning of class on Thursday, 2/26/98 and should be done as part of your review for the Mid Term Exam.

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