If the verset tradition was an important contributor to the development of the 48 both in the concept of the cyclic key scheme and in the combination of prelude and fugue, it was also an important factor in Bach’s concept of fugue. A number of features in the fugues of the 48, which have been considered anomalous in terms of ‘rules’ developed from Bach’s own general practice, are in fact common in this tradition.
Broadly there were two traditions of keyboard fugue in the seventeenth
century: the fuga major, or extended fugue in the stilus gravis, with white note values, and often written in open score; and the fuga minor or short fughetta, generally in madrigal (black) note values, and written on two staves (Riedel 1980 pp.154–5). Groups of these were used in verset collections and, at least in the seventeenth century, were often based on motifs derived from the chant. But there were also various standard subject types, and later subjects included more modern styles such as the Italian trio-sonata type used in Murschhauser’s
Prototypon Longo-Breve Organicum (Nuremberg 1703, 1707). These short fugues
often have the appearance of being isolated sections from the longer sectional genres of ricercar or canzona, and in fact extracts from longer Frescobaldi pieces are found copied into South German verset collections into the eighteenth century (Riedel 1960 p.120). Like such sections, they tend to concentrate on a particular effect, perhaps a dance or some other rhythm, a particular contrapuntal device, or a subject with a particular characteristic. They thus provide examples of fugues based on a single affect, albeit on a miniature scale. Their concise demonstration of devices and affects made them particularly suitable as models of composition.
Many of the fugues of the 48 show more or less signs of this influence. The most obvious case is the C sharp major fugue of Book II which we can see growing in three stages from a brief fughetta in C major on a standard verset figure used in the very popular Wegweiser (first published in Augsburg in 1668 and often reprinted), which Bach may have used for teaching purposes (Walker 1985 p.3). An even shorter figure is in the subject of the E major fugue of Book I: the step in iambic rhythm was a standard motif going back to Frescobaldi’s Fiori musicali. It is possible that other brief subjects such as the A flat major of Book I should also be thought of in this context.
Bach was not interested in chant-based subjects as such in the 48 since his main object was to demonstrate tonal, not modal, harmony. Nonetheless, one of the derivations of the classic subject of the E major fugue of Book II is the outline of the Mode 3 Magnificat chant (normally beginning with the notes g a c: Murschhauser 1721 p.114; see Constantini 1969 p.45), which therefore relates to a Magnificat verset fuga. Character in the subject was particularly desirable so that a succession of versets contrast with each other, often with an increase in the speed of note values with each succeeding fughetta. Expressive, second-practice dissonances such as the diminished 3rd, 4th, or 5th, or the falling minor 6th are features of one type of subject, used notably in Johann Caspar Kerll’s Modulatio organica (Munich 1686).25This is continued in the very seventeenth-century subject of the C sharp minor fugue of Book I, or with the more 18th-century intervals of minor 9th and diminished 7th in the B flat minor fugue of Book I and the A minor of Book II. A subject may have a particular characteristic such as dotted rhythm, as in the B major Fuga in Fischer’s Ariadne Musica or the D major fugue of Book I. A type of subject
using two motifs, the second of which harmonizes with the first so that the fugue can feature stretto, is used in the G minor fugue of Book I (which has often been compared to the E flat major Fuga of Ariadne Musica), based on the same principle; and the D major fugue of Book II, which uses two canzona motifs found in a similar conjunction in the Wegweiser.
Since many versets consist of no more than a single fugal exposition, there is the problem in four parts of ending, as it were, on the wrong foot. With the normal sequence of entries in the pattern subject–answer–subject–answer (dux–comes–dux–comes) the exposition will end on the dominant unless something is added to bring it back to the tonic. A common solution in versets is to have a different sequence of entries, such as dux–comes–comes–dux, so as to end in the tonic. This is the option adopted by Bach in the C major fugue of Book I, a fugue designed to demonstrate the utmost density and economy, so that he can finish the exposition and go straight into the first stretto without any distracting link. A similar procedure is in the F minor and F sharp minor fugues of Book I which have the sequence dux–comes–dux–dux, though in these fugues the fourth entry is separated from the first three by a substantial codetta based on countersubject material.26
A comparison of the fugues that build on the verset tradition (particularly the exhaustive treatment in the Book II fugues in D major and E major) with their verset prototypes is very instructive in demonstrating one of Bach’s main intentions in the 48: to show how traditional materials could still have life and possibilities not yet explored. The irony is that, in proving this by example, he left others with the impression that there was little that they could do better. After 1750 it can hardly be said that composers built on Bach’s achievements in the same vein; rather his achievements became finished objects for contem- plation in theoretical writings.
10. Partimenti
According to C.P.E. Bach, writing to Forkel in 1775, Bach generally composed away from the keyboard except in some, though not all, of his clavier pieces, ‘for which he took the material from improvisations on the clavier’ (Dok.III p.289, NBR p.399). Fugues employing the more elaborate contrapuntal devices were most probably worked out on paper, but others may well be based on improvisation. Mattheson, following Kircher, ranks fugues as part of the Stylus phantasticus together with toccatas and sonatas (1717 p.121), and the ability to improvise them was a necessity for organists in Bach’s environment, being one of the tests for appointment to the better organ posts (Dok.II p.344). Fugal sections in Bach’s earlier clavier toccatas tend to have the feel of written-down improvisations, with their loose structure and stretches of
decorated continuo harmony.
By the early eighteenth century, instruction in fugue in Bach’s tradition grew out of the figured bass, rather than contrapuntal treatises, and so was approached as an improvised genre (Benary 1961 p.33). The technique of this was practised by using fugato movements expressed as figured basses, called in Italian partimento fugues and in German Bassetgen.27Niedt gives an example of one with a promise to say more about how fugues are to be improvised, which unfortunately he did not fulfil (1700 Chapter X). Heinichen also gives an example (1728 pp.515–20, trans. Buelow pp.208–10), and there are numerous ones in manuscript from Bach’s environment. Bach evidently used this method himself for teaching fugue since there are five in the figured-bass instruction, based largely on Niedt, apparently taken down from his dictation at the Thomasschule (ed. Poulin 1994 pp.41–5).
This type of exercise derives from the seventeenth-century continuo practice of doubling the entries in ensemble fugues, the term Bassetgen, equiv- alent to the Italian bassetto, meaning that the lowest part is not in the bass clef.
Partimento fugues have therefore the appearance of trio-sonata continuo parts
without the other instruments. A similar procedure is in the French partition
réduite of a five-part orchestral score to two parts, in which the entries of parts
in, for example, the second section of an overture are copied as a single continuous line, often with changes of clef for each instrumental entry.28The common factor in all these instances is that the subject, where present, is always the lowest sounding part unless written out as a second part above it.
Some pieces strongly suggest that they have been worked up from this type of exercise, such as the Praeludium and Fuga in D minor by Johann Pachelbel in the Mylau tablature (ed. Shannon pp.7–10) in which the prelude is very like a figured-bass exercise and the fugue has all its entries in the lowest part except where there are only two upper voices. The fugues of the 48 are of course much more finished than this, but one may see a reference to it in the exposition of the A major fugue of Book I, on a subject which is in any case based on a continuo formula of rising 4ths and falling 3rds, and with the lowest part having all entries of the subject, including a feigned extra bass entry at b.6. The freedom of improvised fugue still survives residually in the occasional migration of the subject from one voice to another during its course, a feature particularly of French organ fugues, which survives in the C sharp minor and B minor fugues of Book I, and is used as a structural and developmental technique in the B flat minor prelude of Book II.
The most rewarding and systematically worked out exercises are those of Handel, the other most distinguished German improviser of fugues.29These are considerably more sophisticated in that they indicate entries of the subject over the given bass and so can demonstrate the use of double counterpoint and other devices. Alfred Mann has suggested that Handel’s use of Latin for these
voice-entry indicators, and tablature letters for pitch, implies that they are part of a cantoral tradition and that this is how Handel would have begun his study of fugue with his teacher in Halle, Friedrich Wilhelm Zachow.30 They are therefore a series of lessons in fugue from one of the greatest practitioners in Bach’s tradition. At a lesser level, but nonetheless of great interest, is the so- called Langloz manuscript, probably dating from around 1700 in Bach’s area, consisting of a series of partimento fugues which show the relation of versets and
partimenti in a common stock of subjects.31
The most interesting aspect of Handel’s partimenti from the point of view of the 48 is what they reveal of the concept of fugal structure. The exercises develop more elaborate structures as they introduce more contrapuntal devices. They begin with a single exposition, very much in the verset manner, the four parts entering in the sequence dux–comes–dux–comes, with a few bars of continuo harmony at the end to bring the piece back to the tonic. For a longer piece a second exposition is added, balancing the first by reversing the order of entries in a device known as fugal inversion:
dux–comes–dux–comes | comes–dux–comes–dux
For further extension a third exposition may be added, taking in some entries in the relative key. In more elaborately worked fugues this structure of a series of expositions may be combined with unfolding the permutations of invertible counterpoint, as it commonly is in late seventeenth-century trio sonatas such as those of Purcell or, in Bach’s environment, Reinken. Bach reworked three fugues from Reinken’s Hortus musicus (Hamburg 1687) for harpsichord (BWV 954, 965, 966),32and the principle is one he liked to use in his earlier choral fugues.
Alternatively, successive expositions may explore various contrapuntal devices. This structure, without linking material, is particularly suitable for the C major fugue of Book I which explores increasing densities of stretto on a relatively compact scale. Three much larger fugues, among the most elaborate in the 48, also use it and for that reason have often been considered to be among the earlier compositions represented in Book I. Whether that is so, or whether Bach wished at Cöthen to provide examples of this standard fugal structure, it is difficult to imagine it being more powerfully used, with the density of contrapuntal argument contributing to an overwhelming expressive concentration. The double fugue in the E flat major prelude has expositions featuring double counterpoint at the octave, 10th and 12th, as well as stretti. The D sharp minor fugue has, among other features, a very elaborate scheme of normal exposition, followed by one with stretto; then normal exposition with the subject inverted, followed by one with stretto inverso; and finally one with the subject in augmentation. Most daunting of all is the A minor, with a normal exposition; one with the subject inverted; one with stretto recto; one
with stretto inverso; and finally one with stretto recto and inverso at the octave and the 12th. Such a schematic tour de force, combined with the difficulty of performing the piece with its driving Vivaldian metre, must surely be the work of a young turk out to play the others into the ground, and may have been the sort of thing Bach had up his sleeve for the projected competition with Marchand in 1717.