The Grave section from Henry Purcell’s (1659-1695) Trio Sonata No.8 in G, Z.797, begins the final movement and lasts for only nine bars before the tempo indication changes to Vivace for the remainder of the work. Within these nine bars Purcell uses many ingenious compositional techniques which deserve closer investigation.
Preceding the Grave is an Allegro section which concludes with a Perfect cadence in G major (not included in the above score). The Grave section, however, does not appear to continue in G major, as it begins with two chords which are not diatonic to this key: a B major chord in bar 1, and an E major chord in bar 2. Bar 3 begins with a first inversion supertonic chord in G, the first diatonic chord of the Grave, but then introduces an F natural and a C sharp which again contradicts the key of G major. Bars 4 and 5 also introduce accidentals which appear to lead the work further away from G.
Closer inspection of these bars reveals that Purcell does, in fact, remain in G major, not only for the initial bars but for the entire nine-bar length of this section. To find out how the many additional accidentals function in the key of G major we need to look at the underlying structure of the Grave.
Looking first at the continuo part, we can see that bars 2-5 are constructed around a stepwise descent from the G sharp half note in bar 2, down to the C sharp half note in bar 5 (in the analysis below, the descent has been indicated with a continual line while the actual descent in the Grave is displaced with leaps which keep the lowest part within a range of a major 9th).
After a leap in bar 6, another descent begins from the G half note in bar 6 through to the final G in bar 10, and the beginning of the Vivace section.
Over the stepwise descents in the continuo, Purcell has formed two large-scale harmonic areas: the first area prolongs supertonic harmony across bars 3-5, while the second extends tonic harmony from the second half of bar 6 to the beginning of bar 10. These two areas are connected by dominant harmony in the first half of bar 6 . This creates a large ii – V – I cadential progression in G major.
Preceding this cadential progression in bars 1 and 2 is a secondary ii – V progression to the supertonic A minor chord in bar 3.
The harmonic plan (above) explains the use of some of the accidentals in bars 1-5. To explain the remainder we must look at the construction of the two violin parts in bars 3-5.
Over the first appearance of supertonic harmony in bar 3, Purcell begins two melodic lines which ascend chromatically to bar 5: violin 1 proceeds chromatically from E to A, while violin 2 proceeds from A to E; a major third leap from A to C sharp begins violin 2’s chromatic ascent.
These two melodic lines move in thirds (the F natural and G natural in violin 1 can both be rewritten as C sharp and F double sharp respectively), and because they begin and end on notes of the same triad (A minor), they prolong this harmony across these bars (the supertonic is, however, changed from a diatonic minor triad to a major triad in bar 5 with the addition of the C sharp in the continuo).
Within this large-scale supertonic section the interaction of the three parts produces the following harmonies.
In the second half of bar 3, the supertonic seventh chord in 4/2 inversion is a dominant of the dominant of G major: V of V (the F natural in this bar, when rewritten enharmonically as an E sharp, can be heard as the sharpened fifth of the supertonic seventh chord). The D sharp in bar 4 can likewise be heard as the sharpened fifth of the G secondary dominant in that bar). A G secondary dominant seventh chord will typically resolve to a C chord, however, in bar 4 of the Grave Purcell cleverly avoids a resolution to C by omitting the third of the G secondary dominant seventh and the C note in the chord of resolution. Purcell does this by simply moving all of the parts by step from bar 4 into bar 5. This resolution creates an E secondary dominant seventh chord (first half of bar 5) which resolves to chord II in the second half of bar 5. In the continuo part, this resolution is melodically similar to the resolution of the E secondary dominant seventh chord to the supertonic in bars 2-3.
The continuo’s reiteration of C, in bars 3 and 4, and the C sharp, in bar 5, reveals a further long-range chromatic ascent underlying the first half of the Grave.
The continuo’s ascent, when combined with the chromatic violin melodies, reinforces the movement towards the dominant in bar 6.
Compared with bars 1-5, bars 6-9 contain less accidentals . However, as mentioned earlier, the continuo in these bars is also constructed over a stepwise descent: from G to G (again the actual descent is displaced with leaps while the analysis shows a continual line).
Rather than again using ascending chromatic lines over the descending continuo Purcell uses other methods to structure the parts in bars 6-9.
The stepwise descent of the continuo is divided into two sections: bars 6-7 and 8-9. The tied melodic figures in each of these sections is taken from the first half of the Grave (bars 2 and 3),
however, the two-note descent after the tie in bars 6-9 uses larger note values; in other words the notes have been augmented. The use of the same figure in a work creates cohesion and, in this instance, further reinforces the relationship between the notes C and G (although, in bar 2 the G is raised to G sharp). The use of the dotted eighth note-sixteenth note rhythm to precede all of these figures provides further cohesion, this rhythmic figure is used throughout the Grave and is a rhythmic motif.
Over the continuo figures in bars 6-9 Purcell combines two further melodic elements: In the first violin he creates an intervallic pattern which he repeats over both tied continuo figures; the second intervallic pattern begins a perfect fifth lower than the first (the perfect fifth is an inversion of the perfect fourth separating the initial G and C of the continuo’s figures).
In the second violin Purcell adds a melodic line which essentially moves by step and creates a voice-exchange with the first tied continuo figure, and moves in thirds with the second.
The interaction of these three parts creates another extended ii – V – I cadential progression in G, which leads into the Vivace section in bar 10.
The Grave’s long-range harmonic basis can be summarised as follows:
From this example, it is clear that the note C, whether used as part of supertonic harmony (bars 3 and 5) or subdominant harmony (bar 8), unites the two parts of the Grave’s nine-bar duration. C’s relationship to the tonic G is also shown, not only across the entire nine bars of the work but also with the inclusion of the tied figures in bars 2 and 3 and 6-9. Purcell’s ability to combine these structural factors: the stepwise continuo parts with the ascending chromatic violin lines in bars 3-5, and the intervallic patterns of bars 6-9, reveals his great skill as a composer.