Classical theme functions

This page is a quick-reference. For examples of these functions in musical contexts, see the resource on Classical theme types.

Presentation

Presentation function comes at the beginning of a theme or phrase. It involves the establishment of the primary melodic material (usually through the use of one or more statments of a basic idea) and the establishment of the tonality of the theme (usually through tonic prolongation).

Continuation function

Continuation function comes in the middle or late-middle of a phrase or theme, after presentation function has already been expressed. It typically involves the breakdown of the primary melodic material and harmonic acceleration towards the cadence.

Following are important terms/concepts associated with continuation function. Not all need be present for a passage to express continuation function, but some should be.

• Fragmentation – Breaking the melody into smaller chunks (for example, following two-bar basic ideas with one-bar fragments of the same melodic material).
• Liquidation – Gradually replacing the characteristic or unique parts of a melody with conventional or common elements.
• Sequential repetition – Repeating the same melodic or harmonic element two or three times, transposed to different pitch levels. This is often used in conjunction with fragmentation.
• Acceleration of melodic rhythm – Changing from predominately quarter notes and eighth notes in the melody to predominately eighth notes and sixteenth notes, for example.
• Acceleration of harmonic rhythm – Chord changes coming more frequently (changing from one chord per bar to two chords per bar, for example).

Cadential function

Cadential function comes at the end of a theme or phrase, after presentation and continuation functions have been expressed. It typically involves a cadential harmonic progression and a conventional, descending melodic pattern.

A classical cadential progression begins with the last chord of tonic prolongation and ends with a cadential arrival. The three typical types of cadential arrival in Classical music are the perfect authentic cadence (PAC), the imperfect authentic cadence (IAC), and the half cadence (HC).

A half-cadential progression will begin with the final T chord, progress (optionally) through S, and arrive on a cadential D chord (always D5):

T__ (S__) D5

An authentic-cadential progression will begin with the final T chord, progress (optionally) through S, and end with the cadential D T progression (always D5 T1):

T_ (S_) D5 T1

General notes

Just as there is exactly one progression through T (S) D T for every cadence in classical music, there is exactly one progression through presentation – continuation – cadential functions for every cadence in classical music.

None of these functions are optional; all must be present in a normative formal progression.