The early 20th-century music theorist Heinrich Schenker (1868–1935) was responsible for developing both the conceptual framework for prolongation and a means of analyzing music in terms of prolonged musical structures (called
Schenkerian analysis). Schenker’s own usage of the term differs from the modern one. The German word
Prolongation is not common, and Schenker first used it in a very specific meaning (maybe originating in legal, possibly Viennese vocabulary), referring to the extension of the primal laws (
Urgesetze) or of the primal concepts (
Urbegriffe) of strict composition in free composition and the phenomena resulting from the extension of these laws. He used the word mainly to denote the transformation of a given level of
voice-leading to the next one, describing the passage from level to level as a
Prolongation.
Adele T. Katz appears to be responsible for the shift of meaning where "prolongation" became the American translation of
Auskomponierung. In his analysis of
J.S. Bach's
Little Prelude in D minor, BWV 926, in
Der Tonwille 5, Schenker proposes what may be his earliest figure showing the steps through which the
Ursatz develops into the
foreground. He explains that this figure "shows the gradual growth of the voice-leading prolongations, all predetermined in the womb of the
Urlinie". The "gradual growth" illustrated is a global phenomenon, always concerning the piece as a whole. The figure is further commented upon on p. 45 of the same volume. Schenker stresses that it starts with the two-voice setting of the
Ursatz – an expression, therefore, of the fundamental laws of strict
counterpoint. Each of the following steps is described as a
Prolongation, a specific freedom taken with respect to the laws expressed in the previous step. And in
Freie Satz, he confirms that the word still refers to the passing from one voice-leading level to another: "For the sake of continuity with my earlier theoretical and analytical works, I am retaining in this volume the words of Latin derivation
Prolongation and
Diminution as designations for the voice-leading levels in the middleground". The concept of
Prolongation is important for Schenker because he believes that showing how a masterpiece of free composition remains rooted in the laws of strict counterpoint explains its utter unity, its "synthesis". The means and techniques of passing from one level to the next are subsumed in Schenker's notion of "composing out" or "compositional elaboration" (
Auskomponierung, a German neologism), which for him is a mechanism of elaborating pitch materials in musical time. in seven steps: (1) Schenker proposes it as an operational concept in his teaching; (2)
Felix Salzer,
Allen Forte and others, disseminate and clarify it; (3) it is used within attempted formalisations of Schenkerian analysis; (4) new theories evoking Schenker make use of it; (5) it is used within theories amplifying Schenker's own; (6) definitions are proposed in theories beyond the Schenkerian canon; and (7) definitions of the term are proposed in relation to
atonal music. The replacement of Schenker's own term
Auskomponierung by "prolongation" appeared in step (2), as an English translation. The English "prolongation" has been used in
The Masterwork in Music to translate German words including
Auskomponierung,
ausdrücken and
Auswicklung. In
Free Composition, "prolongation" is more than once used to translate
Auskomponierung and "prolonged" for
auskomponiert. Oster otherwise translates
Auskomponierung as "composing out" and others use "compositional elaboration" or, short, "elaboration." Drabkin quotes as "methods of prolongation" techniques that include
Anstieg,
Ausfaltung,
Koppelung,
Tieferlegung,
Übergreifen and
Untergreifen, which Schenker would rather have described as techniques of
Auskomponierung. ==Prolongational techniques==