# IV. Diatonic Harmony, Tonicization, and Modulation

This section introduces students to how Western classical composers use harmony to create a sense of trajectory in a phrase of music. It begins with basic diatonic harmony and ends with tonicization and modulation to closely-related keys.

# Prerequisites

This section assumes a familiarity with the topics covered in Fundamentals. It’s helpful, but not necessary, for students to have studied some counterpoint as well, particularly the introductory chapter.

# Organization

The chapters are organized around two principles: (1) the and (2) bass-line patterns. The section starts by examining phrase endings since these are relatively formulaic, then moves to beginnings, and finally takes on middles.

The first chapter introduces the phrase model, defines , and discusses how composers create phrase endings via . It only uses I and V chords.

In the next four chapters, students learn to strengthen cadences using V7 (root position only) and strong (IV and ii(6)), and the $\mathrm{cadential}^6_4$. It’s important that students learn about embellishing tones before reading the $\mathrm{cadential}^6_4$ chapter.

The next six chapters complete the study of diatonic harmony, first focusing on how to expand tonic at the beginning of the phrase, then on how to create length in the middle of a phrase.

The section ends with tonicization and modulation, though note that the tonicization chapter could be done in two parts: part one on tonicizations of V only, and part two on tonicizations of chords other than V.