It is well known that the instrumental fugue was born of this species of composition, which was also called canzon francese; the responses to a subject, sometimes of popular origin, and most often in this rhythm (a traditional one):
[[audio/mpeg]] [[MusicXML]] became answers, and the alternation of double with triple rhythm gave rise to the fugue in several movements, such as Buxtehude, in particular, often wrote.
The steps of this transformation may be traced in the canzoni of Frescobaldi: the canzone in the fourth mode of the Fiori musicali (p. 66) is an instance of an altered answer to a subject, and the Canzone IV (p. 53) of the second book (Toccatas, Canzoni, etc.[15]) begins like a veritable fugue:
For us the recercare possess an interest of another kind; Frescobaldi had introduced an innovation in creating the initial form of the fugue, unconsciously guided by the necessity of establishing the modern tonality which forced itself upon his senses; particularly in the Ricercatas and in certain of the Toccatas he contrives to become master of a new resource, which had suggested this tonality to him: the chromatic scale.
This enables him to discover new harmonies, although he is sometimes led astray, and to modulate with endless freedom. The dissonance is no longer a "necessary evil" to him; it is an important factor in new effects. With his absolute command of the instrument and his marvellous facility of improvisation, this ability to distance his contemporaries in a field which up to this time no one had had the courage to explore, places the organist of St. Peter's in a position closely allied to that occupied by the Cantor of Leipzig; at least considering what Frescobaldi was able to accomplish in his time, obliged to create a new language for himself, as it were; and he sometimes lost his way, in propounding to himself problems which were insoluble in the existing stage of musical advancement.
Possibly Frescobaldi realized this impossibility of a personal participation in something which he foresaw, as yet only in a confused way, but whose advent he regarded as a certainty. For since he could neither ordain a "music of the future," to use an expression already more or less familiar, nor define its fundamental principles, he was often obliged to deny himself any part in even the development of his art, confined as he was to the limits of obsolete rules; did he also conclude that his too fertile imagination would lead him into extravagances, and did he voluntarily restrain this creative faculty, confining it to the laborious construction of too subtle enigmas? Certain of his compositions suggest such a condition of mind; above all, the Recercar con obligo di cantare la Quinta Parte senza toccarla (Fiori musicali, p. 84).[16]