In lectures and essays, Ligeti stressed the role of memory and historical conditioning in the conception of form and meaning in music. His sketches frequently mention music from Couperin to Mahler as a model for different features of his own. These, in turn, become the basis for expressive gestures, referencing elements of traditional music as well as familiar types from Ligeti’s own oeuvre. While it is tempting to look at the titles of works like Clocks and Clouds (after Karl Popper), San Francisco Polyphony, and Three Pieces for Two Pianos (Monument, Selbstportrait, Bewegung) as starting to build toward the expressive ends of the opera, Le Grand Macabre, this trend can actually be found in works with more abstract titles, including his String Quartet no. 2 and Ten Pieces for Wind Quintet. This historical awareness, essential to Ligeti’s music, positions him on a fine line between the modernist and postmodernist eras.