Fourth Species Guidelines and Fifth Species
As in Second Species, the half note on the first beat is defined as strong, and the second half note is weak. The rhythm of Fourth Species is note-against-note, offset or delayed by one beat. The weak beat in the counterpoint is always tied across the bar line and may become a Suspension when the other voice moves on the strong beat. If it is a consonance when the other voice moves, it is referred to as a Syncope rather than a suspension. Fux referred to tied notes as “Ligatures.”
Fourth Species consists of counterpoint with Suspensions and Syncopations. A suspension is a note that is held across a strong beat, and when the other note in the counterpoint moves it becomes a dissonance. The suspension is prepared (preceded) by a tied common tone and resolves down stepwise to a consonance. The three notes in the counterpoint that create the suspension are the Preparation, the Suspension, and the Resolution (PSR).
The Preparation is a consonance, may occur on either a strong or weak beat, and is equal to the suspension in duration. The Suspension is typically a 4th resolving to a 3rd (4-3), a 7th resolving to a 6th (7-6), and less often a 9th resolving to an octave (9-8). It happens on the strong beat in the upper voice. The primary type of Suspension that occurs in the lower voice is the Bass Suspension, consisting of a 2nd to a 3rd (2-3). It is an inversion of the 7-6 suspension. The Resolution is an imperfect consonance, not a unison, and is always a step below the suspension itself. A 4-5 suspension in the lower voice is very rare.
When the same rhythmic formula occurs between the two parts, and the intervals are a 6th to a 5th (6-5) between them, it is referred to as a Syncopation rather than a Suspension. This is because the intervals are both consonances. As in Second Species, it is permissible to leap to and from a consonance. This is often done to reposition the voices for a suspension. The 2-1 and 7-8 sequences of intervals are avoided.
As you write and analyze Fourth Species, you will find that certain combinations of intervals recur. There are a limited number of patterns, depending on the movement of the Cantus Firmus. When writing the CP in the upper voice there are two obvious patterns. If the CF steps upward, an octave in the CP becomes a 7th, which must resolve down to a 6th. If the CF steps down, a 3rd becomes a 4th in the counterpoint, which must resolve down to a third. It is common to create chains of consecutive 7-6 and 4-3 suspensions over stepwise motion in the CF. Ending with a Clausula Vera, as all these examples do, the 7-6 in the penultimate measure resolves smoothly to the octave.
Rules for Fourth Species (whole notes against tied half notes)
- In the upper voice, write a consonant half note on beat 3 and tie it over the bar line. Select a consonance with the potential to become a suspension over the moving Cantus Firmus.
- If it becomes a dissonance, such as a 4th or 7th when the CF moves, resolve it down stepwise to a 3rd or 6th.
- If the tied note remains a consonance, you may leap away from it to a note that becomes the preparation for another suspension. If it becomes a dissonance, resolve it down stepwise creating another suspension.
- Parallel 5ths on consecutive strong beats separated by consonances are acceptable. This also applies to octaves, but only two in a row.
- The penultimate bar ends with a half note that is not tied, and the last bar contains whole notes forming a Clausula Vera.
Fifth Species (Florid Counterpoint)
Fifth Species combines all the other species. Generally, common time is used, and no more than two consecutive measures with identical rhythmic patterns are written. The use of parallel perfect intervals is determined by those governing the species used at any given time.
Rules for Fifth Species (for use in writing examples)
- Quarter notes are typically the shortest note values used against whole notes in the CF, except in ornamented suspensions.
- Prepare suspensions with a half note, and use either a half or quarter note for the suspension itself.
- Avoid the quarter-quarter-half note combination in a measure, unless the half note is tied into the next measure.
- Avoid quarter-half-quarter in a measure, which creates excessive sycopation.
- The half-quarter-quarter note combination is allowed, following the rules governing the species used.
- Note values in the penultimate measure are governed by the species used, moving into the standard Clausula Vera cadence.
de Lassus: Oculus non vidit (1577)