1. Tonal prolongations are present from the beginnings of true polyphony. Even though the procedure is mosaic (i.e., represented by chains of small units) in each of the units, the triad, major or minor, is horizontalized, thus indicating the almost immediate establishment of the triad as the basic organizing property.
2. The history of musical structure of these almost five hundred years reveals a constant growth in the use of the triad as an organizing force. Its history is continuous as well as gradual, whereas differences in the small details of the immediate foreground, the turf of traditional style analysis, are sometimes marked.
3. Modality and tonality are not opposites. Modes in polyphony are not pure and are constantly altered, with the notable exception of the Phrygian. Through alternation these modes tend to resemble more and more the major or the minor mode. The leading tone, through ficta or stipulation, is an early occurrence, resulting in emphasis of the central tone.
4. The leap of a fifth in the bass, a concept which is not linear, evolves from the fourteenth century onwards as a property of tonal relationships. During the fifteenth century the dominant phenomenon is well established. While the dominant sometimes appears internally as a minor triad, thereby lacking the leading tone, its force, though attenuated, still effects harmonically defining motion.
5. Outer form, stemming from the form-creating sources of poetry and dance, fuses with tonal direction, thus creating tonal form. Interruption, an important principle of structure that reflects the overall conditioning force of triadic tonality in creating form, emerges at a relatively early stage.
6. Inner form, or the organization of internal space, becomes identifiable through the techniques of repetition. Motivic elements, both melodic and rhythmic, join with tonal direction to create spatial entities which likewise are frequently interrelated. Interruption often plays a role in the realization of inner form.
7 The Urlinie of the top voice makes itself clearly felt at a very early stage, with recurrent motions of direct descent outlining the triad, the octave, or the lower third of the triad repeatedly revealed in examples. Ascending motions to a tone with structural property occur with considerable frequency.
8. Frequently the motion of the Urlinie is to the leading tone as a penultimate point before the first degree. The leading tone acts as an inner voice below the second degree, as is characteristic in later musical practice.
9. The lowest voice frequently supports tones of the Urlinie contrapuntally rather than harmonically. This takes place in the representation of the background as well. The emergence of fully harmonic structure is gradual and steady, increasing rapidly in the sixteenth century.
10. Prolongations of chords other than tonic occur with increasing frequency. Such prolongations also apply to chords which are harmonic and so function in the background.
11. The techniques of prolongation are varied, involving many of the same procedures that characterize the music of the eighteenth and nineteenth centuries, e.g., voice exchange, neighbor-motions (complete, incomplete, and combined), passing chords, motion to and from the inner voice, superimposition of the inner voice.
12. The distance between foreground and background varies. It is less so in the early examples, more so in the sixteenth century. The small spatial elements and the general absence of registral shifts prior to the sixteenth century eliminate the need for a number of hierarchical levels. Further, the frequent demonstration of the complete definitive Urlinie descent and total background representation at the last stage of the composition eliminate the didactic need to separate Ursatz from middleground.
13. Mode may have no bearing on the final Ursatz, i.e., the outer voices would not reflect any condition that is not typical of the Ursatz representation in either major or minor. The Phrygian mode is, of course, an exception.