Getting Started
Having learned to identify individual chords with Roman numerals, we now explore how these chords connect to form meaningful musical sentences. This chapter introduces the core principles of harmonic progression, where chords are not just isolated events but have specific roles or "functions" that create expectation and resolution. Understanding these functions is the key to analyzing how tonal music flows and creates a sense of direction and closure.
What You Should Be Able to Do
Provide a Roman numeral analysis for a given harmonic progression.
Label the harmonic function (tonic, predominant, or dominant) of each chord in a progression.
Identify the five principal cadence types from a musical score.
Aurally distinguish between conclusive and inconclusive cadences in a musical excerpt.
Describe how harmonic function governs the order of chords leading to a cadence.
Key Concepts & Analysis
In tonal music, harmony is not random; it follows a logical syntax, much like grammar in language. This syntax is known as functional harmony. It proposes that every chord in a key has a contextual role that contributes to the overall sense of journey away from and back to a stable home base. These roles, or functions, fall into three main categories: Tonic, Predominant, and Dominant.
Functions & Allowable Motions
The standard model for harmonic progression is a cyclical pattern that moves from stability, to instability, to resolution. This creates a powerful sense of forward momentum.
Tonic (T): This is the function of stability and rest. The tonic chord (I in major, i in minor) is the harmonic home base. Progressions begin and end here. The submediant chord (vi or VI) can sometimes substitute for or prolong the tonic function.
- Typical Motion: Tonic can move to any other function.
Predominant (PD): This function creates moderate tension and serves as a transition away from the tonic area, preparing for the arrival of the dominant. The most common predominant chords are the subdominant (IV or iv) and the supertonic (ii or ii°).
- Typical Motion: Predominant chords most often move to the dominant.
Dominant (D): This is the function of maximum tension and instability. The dominant chord (V) contains the leading tone (^7), which has a strong melodic pull back to the tonic (^1). Its primary job is to create a powerful expectation for resolution to the tonic chord. The leading-tone triad (vii°) also serves a dominant function.
- Typical Motion: Dominant chords almost always resolve to the tonic.
The most common and logical path for a harmonic progression is Tonic → Predominant → Dominant → Tonic. While variations exist, this foundational sequence (T → PD → D → T) accounts for the vast majority of progressions in the common practice period. Moving backward against this flow (e.g., D → PD) is called a harmonic retrogression and is used sparingly for special effect.
Common Progressions
These short progressions demonstrate the T → PD → D → T model in action:
I–IV–V–I
I–ii–V–I
i–iv–V–i
I–vi–IV–V–I
i–VI–ii°–V–i
Cadence Implications
A cadence is a point of relative repose that concludes a musical phrase, acting as harmonic punctuation. The type of cadence is determined by the final two chords of the phrase and their harmonic function. Cadences are broadly categorized as either conclusive (providing a sense of finality) or inconclusive (leaving the listener expecting more).
Conclusive Cadences: These cadences provide a strong sense of closure, making them suitable for ending major sections or entire pieces.
The Perfect Authentic Cadence (PAC) is the strongest and most final-sounding cadence. It consists of a root-position V chord moving to a root-position I chord, with the tonic pitch (^1) in the highest voice of the I chord. (D → T)
The Plagal Cadence (PC) is also conclusive but gentler. It consists of a IV chord moving to a I chord. (PD → T). It is often called the "Amen" cadence.
Inconclusive Cadences: These cadences create a pause or a feeling of continuation, making them suitable for ending antecedent phrases or connecting musical ideas.
The Half Cadence (HC) ends on a V chord. Because the dominant function creates tension, a half cadence leaves the music feeling unfinished, as if pausing for a breath. It can be preceded by any other chord. (? → D)
The Imperfect Authentic Cadence (IAC) consists of a V–I progression (D → T) but lacks the ultimate finality of a PAC. This weakening of closure is achieved in one of two ways: either one or both chords are inverted, or the highest voice of the I chord ends on a pitch other than the tonic (^3 or ^5).
The Deceptive Cadence (DC) creates surprise by avoiding the expected tonic resolution. It consists of a V chord moving to a vi chord (or VI in minor). The progression begins as if it will be an authentic cadence, but it is "deceived" at the last moment. (D → T-substitute)
Data & Organization Tools
A simple way to visualize the flow of functional harmony is through a function map. Arrows indicate the most common and logical paths for chord progressions.
Harmonic Function Map
Tonic (I, vi)
I → can go to PD or D
vi → can go to PD or D
Predominant (IV, ii)
IV → can go to D
ii → can go to D
Dominant (V, vii°)
V → can go to T
vii° → can go to T
Primary Path: I → (vi) → (IV or ii) → (V or vii°) → I
Evidence Bank
Harmonic Function: The contextual role a chord plays in creating or resolving tension within a progression (Tonic, Predominant, or Dominant).
Tonic Function: The role of harmonic stability and rest, embodied by the I chord.
Predominant Function: The role of transitioning away from tonic and preparing the dominant, embodied by IV and ii chords.
Dominant Function: The role of creating maximum harmonic tension that demands resolution to the tonic, embodied by the V chord.
Cadence: The chords that end a musical phrase, creating a sense of pause or finality.
Conclusive Cadence: A cadence that provides a sense of closure, such as a Perfect Authentic or Plagal Cadence.
Inconclusive Cadence: A cadence that sounds incomplete or creates an expectation for continuation, such as a Half, Imperfect Authentic, or Deceptive Cadence.
Perfect Authentic Cadence (PAC): A V–I progression where both chords are in root position and the tonic pitch is in the highest voice of the I chord.
Imperfect Authentic Cadence (IAC): A V–I progression where either chord is inverted OR the tonic pitch is not in the highest voice of the I chord.
Half Cadence (HC): A cadence ending on the V chord.
Plagal Cadence (PC): A IV–I progression.
Deceptive Cadence (DC): A V–vi (or V–VI) progression.
Skill Snapshots
Functional: The progression I–vi–ii–V–I is functionally sound because it follows the T → PD → D → T model. The tonic (I) moves to a tonic-substitute (vi), which then moves to a strong predominant (ii) to prepare the dominant (V), which resolves conclusively to the tonic (I).
Functional: The progression i–iv–V–i in a minor key works for the same reason. It moves from tonic stability (i) to predominant preparation (iv), builds tension with the dominant (V), and resolves that tension by returning to the tonic (i).
Functional: A progression like I–V–IV–I contains a harmonic retrogression (V–IV). While musically possible, it subverts the standard functional flow (D → PD) and is therefore less common and goal-oriented than a progression like I–IV–V–I.
Form: A phrase ending with a half cadence (ending on V) feels like a question, requiring an answer. A subsequent phrase ending with a perfect authentic cadence (V–I) provides that answer, creating a common question-and-answer phrase structure.
Form: The deceptive cadence (V–vi) is a powerful tool for extending a phrase. By avoiding the expected tonic closure, the composer can delay the final cadence and build more musical drama.
Common Misconceptions & Clarifications
"Any V–I progression is a PAC." Clarification: For a V–I cadence to be a Perfect Authentic Cadence, both chords must be in root position and the highest voice must end on the tonic note (^1). If either of these conditions is not met, it is an Imperfect Authentic Cadence.
"A cadence is just the last chord." Clarification: A cadence is defined by the relationship between (at least) the final two chords of a phrase. The function of the penultimate chord is just as important as the final chord in determining the cadence type.
"The plagal cadence feels as final as an authentic cadence." Clarification: While both are conclusive, the plagal cadence (IV–I) lacks the strong leading-tone-to-tonic resolution of the authentic cadence (V–I). This gives it a less dynamic and more serene sense of closure.
"All progressions must strictly follow T → PD → D → T." Clarification: This model describes the strongest and most common path of harmonic motion. Composers frequently use variations, such as moving directly from T → D (e.g., I–V–I) or using tonic prolongations (e.g., I–vi–I), but the general drive towards the dominant to prepare the tonic remains the central principle.
Summary
Harmonic progression in tonal music is guided by the principle of functional harmony, a system where chords are categorized by their role as tonic, predominant, or dominant. The logical flow between these functions, typically Tonic → Predominant → Dominant → Tonic, creates goal-oriented motion and musical coherence. This progression culminates at a cadence, a point of harmonic punctuation that concludes a phrase. Cadences are classified as conclusive (Perfect Authentic, Plagal) or inconclusive (Half, Imperfect Authentic, Deceptive), shaping the listener's sense of closure and expectation. By analyzing progressions through the lens of function and cadence, we can understand the fundamental grammar that underpins the structure and emotional arc of tonal music.