ABSTRACT
It is one of the notable ironies of recent music history that Heinrich Schenker's concept of prolongation has supplied an important tool for the analysis of twentieth-century music. Schenker conceived of prolongation solely in terms of a consonant, triadic background; and the technique was, in his own formulation, strictly limited to the framework of the functional tonal system. Theorists have more recently begun to point out tonality-defining prolongations in twentieth-century compositions that form surprisingly close parallels to earlier triadic procedures. Schenker remarks that the graphs are at best indications of "what may have been dimly present in Stravinsky's mind." Yet, as he proceeds to point out, there do exist horizontal prolongations of intervals (Zuge or "spans"), although the spans are "of the simplest type." In Liszt's late piano pieces there are several instances of complete, independent compositions organized entirely by means of dissonant prolongations.
