Church modes originated in the medieval era, and are classified by their use of the diatonic collection, their final, the relationships of other pitches to that final, and their range.

In the 20th and 21st centuries, diatonic modes are also understood as rotations of the major scale, without range requirements, but with the concept of a pitch-class center or tonic.

Non-Western musical cultures have their own methods of organizing pitch into modes. These "modes" are usually more than simple pitch collections and can include characteristic gestures, embellishments, and protocols for use. Examples include Indian raga, Arabic maqam, Balinese pelog and slendro, Jewish prayer modes, Persian dastgah, and Japanese scales.

Modes, conceived in terms of parallel relationships, with an emphasis on the color notes of each mode:

Ionian: Identical to major

Mixolydian: Like major with a \downarrow\hat{7}

Lydian: Like major with a \uparrow\hat{4}

Aeolian: Identical to natural minor; no raised leading tone

Dorian: Like natural minor with a \uparrow\hat{6}

Phrygian: Like natural minor with a \downarrow\hat{2}

Modes, conceived in terms of relative relationships:

Ionian: White notes starting on C

Dorian: White notes starting on D

Phrygian: …starting on E

Lydian: …starting on F

Mixolydian: …starting on G

Aeolian: …starting on A

This book covers modes from many different angles. For more information on modes, check Introduction to Diatonic Modes (general), Chord-Scale Theory (jazz), Modal Schemas (pop), and Analyzing with Modes, Scales, and Collections (20th-/21st-c.).

At the turn of the 20th century, many composers were rethinking the materials of music. This is one reason the term “common practice” is used to distinguish the major-minor music that dominated Western classical music for the 200 years or so prior—something changed around 1900. You’ll also hear talk of the "emancipation of the dissonance" connected to this, and the emergence of atonality out of ever-more-radical chromatic maneuvers. The history of music is much more complex than this simple take, but there is some truth to it: a lot of composers were interested in reinventing what and how they composed, similar to the emergence of abstract art around the same time.

The use of modes has a place in all of this, encapsulating many of the ways in which one can broaden the compositional palette. In this chapter, we’ll go through some of the most interesting, famous, and significant options, starting, as many composers did, by looking back to what came before.

Church Modes

The dominance of major and minor in Western classical music emerged out of an earlier practice centered on the use of modes. This collection of modes is often called church, white-note, or Gregorian modes. These modes correspond to rotations of the C major scale, using the same collection of pitches but a different tonic (more properly referred to as a final in this context).

This already introduces us to a fundamental tenet of what a mode generally comprises: both a diatonic collection of pitches and a final. These are the first two items on the list below, followed by two other particularly useful concepts for understanding church modes:

The diatonic collection and the intervallic relationships between those pitches

The final, which acts as a referential point

Further hierarchical levels between the pitch in the mode and its final

Melodic shapes and range

1–3 will be familiar from tonal music, but 4 may not be. Range is a defining characteristic of the church modes, as each mode has an authentic and a plagal version.

Example 1 summarizes the modes by their final, their tenor, and their range. Authentic modes are on the left, while plagal modes (those beginning with "hypo-") are on the right. Tenors are usually a fifth above the final in authentic modes and a third above the final in plagal modes (except where noted with an exclamation point). Example 2 provides the same summary, but in notation.

Example 1. The historical church modes summarized.



Example 2. The historical church modes summarized in notation.

Diatonic Modes in the 20th and 21st centuries

Another summary of diatonic modes (and assignments on them) can be found in Introduction to Diatonic Modes and the Chromatic "Scale."

When modes were revisited as a compositional concept in the 20th century, many concepts from church modes were maintained, while other distinctions were erased. The notion of authentic/plagal modes ("hypo-" modes) was dropped, as the range of many pieces spans more than one octave. Additionally, Glarean's later modes, aeolian and ionian, were just as important as the original authentic church modes.

Color notes

As a listener, you may experience modes as sounding similar to major or minor, but with certain inflected notes—color notes.Vincent Persichetti (1961) referred to these notes as "characteristic notes." Modes will sound major-ish or minor-ish based on the quality of the third above the tonic. The major-ish modes are mixolydian and lydian; the minor-ish modes are aeolian, dorian, and phrygian.

Example 3 lists each mode, the quality of the third above the tonic, its color note that distinguishes it from major/natural minor, and its pitches parallel and relative to C major.

Example 3. Important characteristics of each mode.

Example 4 provides a brief summary of this information using notation. The modes are grouped by whether the tonic is major or minor, which helps with aural identification of modal passages (as discussed further below). The top li