Iacobus Leodiensis [Iacobus de Montibus, Iacobus de Oudenaerde]

(vi) Melodic variations.

In addition to the free-form ornamentation described above, it seems to have been customary for shorter movements to receive added sets of figural, melodic variations following the playing of the movements that served as their ‘theme’, even if that theme already had its reprises decorated. Georg Muffat referred implicitly to this practice in the preface to his concerti grossi of 1701, saying that the ‘liveliest airs [are to be played] thrice (with all [their] repeats)’. By using a system of distinct characterized variations, a short movement of this type could gain added cohesive structure as well as length, while demonstrating the improvisatory skill of the performer. Once again, the best period examples are found in the music of Corelli, where gavottas and gigas are extant both in freely decorated versions and extended with sets of variations. Frequently, individual movements with added variations exist without reference to the entire sonatas that originally contained them – the basis for the later Classical theme and variations.

Improvisation, §II, 3: Western art music: Baroque period

(vii) Cadenzas.

A special instance of free improvisation is the cadenza (for a fuller account seeCadenza). In his section on cadences Quantz defined them as

those Embellishments commonly introduced on the last Note but one, mostly on the Fifth of the Key … the Productions of the momentary Invention of the Performer. Regular Time is seldom to be observ’d in Cadences … Those for Voice or Wind Instruments ought to be short and so manag’d that they may be perform’d in one Breath, but those for String Instruments are not limited, but the Performer has so much Latitude given him, as his own skill and fruitfulness of Invention will permit, but notwithstanding will gain more Applause from the Judicious by a moderate length than otherwise.

The short cadenza ‘within a breath’ and the extended solo fantasy are exemplified and contrasted in the works and performing practices of two famous early 18th-century violinists, the Roman Corelli and the Venetian Vivaldi. At the close of Corelli’s sonata and concerto grosso movements it is not uncommon to find, immediately before the final cadential trill, a flourish that recalls the slurred gruppi of the ‘graces’ in the Sonatas. By contrast, reports of Vivaldi’s pyrotechnic abilities, not always immediately evident in the texts of his concertos, are amply demonstrated in the lengthy manuscript cadenzas for the Concerto in Drv208 (‘il Grosso Mogul’), which came to light in the 1980s. Further, Pietro Locatelli, the most technically accomplished virtuoso before Paganini, published as Capricii the extended and difficult cadenzas for the concertos of his 1733 L’arte del violino op.3. C.P.E. Bach, in his Versuch über die wahre Art das Clavier zu spielen (1753; end of chap.2), also discussed cadenzas in terms of fermatas appearing at cadences as well as other places (trans. W.J. Mitchell, 1949):

Fermate are often employed with good effect … there are three places at which the fermata appears: over the next to the last, the last, or the rest after the last bass note … Fermate over rests appear most frequently in allegro movements and are not embellished. The two other kinds are usually found in slow, affettuoso movements and must be embellished if only to avoid artlessness. In any event elaborate decoration is more necessary here than in other parts of movements.

The cadenzas improvised in da capo arias by singers such as the famous castrato Farinelli often ran to inordinate length, notwithstanding the stricture that they should be sung in one breath. Tosi (op. cit., 128–9) criticized such cadenzas thus:

Every Air has (at least) three Cadences, that are all three final. Generally speaking, the Study of the Singers of the present Times consists in terminating the Cadence of the first Part with an overflowing of Passagges and Divisions at Pleasure, and the Orchestre waits; in that of the second the Dose is encreased, and the Orchestre grows tired; but on the last Cadence, the Throat is set a going, like a Weather-cock in a Whirlwind, and the Orchestre yawns.

The gigantic written-out cadenza for the harpsichord in the first movement of Bach’s Fifth Brandenburg Concerto is an excellent example of its type, though it may be considered too extensive for the usual extemporization and even to constitute an example of the soloist’s abuse of privilege. When the two outer movements of a Baroque concerto – or indeed any two movements in any other type of work – are separated only by two chords, usually constituting a Phrygian cadence, the first of them should be elaborated into an improvised cadenza; a familiar instance occurs in Bach’s Third Brandenburg Concerto.

Improvisation, §II, 3: Western art music: Baroque period

(viii) Continuo realization.

Developments in the realization of the thoroughbass kept pace with the elaboration of the melodic line in the late Baroque period (for a fuller account see Continuo). The most exhaustive treatment of this subject is by Heinichen in Der General-Bass in der Composition (1728). He declared that the simple three-part realizations of the 17th century were old-fashioned and advocated the doubling of chords in both hands and the introduction of improvised ornamentation. He provided (i, chap.6) three realizations of a single bass line (ex.14), first in a simple manner (a), which can be avoided by introducing ornamentation and a true melodic line in the right hand (b); or, to give even more freedom to the melodic line, the chords may be played entirely by the left hand (c).

Early 18th-century Italian continuo practice went far beyond Heinichen, especially in the accompaniment of recitatives. Gasparini’s L’armonico pratico al cimbalo (1708), Joseph de Torres y Martinez Bravo’s Reglas generales de acompañar, en organo, clavicordio y harpa (enlarged 2/1736), which cites Gasparini with clearer musical examples, and Alessandro Scarlatti’s Varie introduttioni per sonare e mettersi in tono delle compositioni (GB-Lbl Add.14244) give rules for the addition to triads of handfuls of acciaccaturas, to be played ‘quasi arpeggiando’. But other examples, now and later in the century – for instance in Niccolo Pasquali’s Thorough-Bass Made Easy (1757) – are more subdued.

There are first-hand accounts of Bach’s continuo improvisation. L.C. Mizler wrote (1738) of his accompanying ‘every thorough-bass to a solo so that one thinks it is a piece of concerted music and as if the melody he plays in the right hand were written beforehand’ (translation from Aldrich, 1949). C.P.E. Bach related that his father liked to extemporize a fourth part when accompanying a trio. Bach’s pupil J.C. Kittel described (Der angehende praktische Organist, iii, 1808, p.33) how Bach would become impatient with the inadequate accompaniment of a pupil and how ‘one had to be prepared to find Bach’s hands and fingers mingling with the hands and fingers of the player and, without further troubling the latter, adorning the accompaniment with masses of harmony, which were even more impressive than the unexpected proximity of the strict teacher’. Two of Bach’s accompaniments are thought to be examples of his own realizations in written-out form, since they are marked ‘cembalo obligato’ and are not in the same style as his usual composed harpsichord parts: they are those of the second aria in the solo cantata Amore traditore bwv203 (thought to be by Bach) and of the second movement of the Sonata in B minor for flute and harpsichordbwv1030.

Improvisation, §II, 3: Western art music: Baroque period