Frescobaldi’s influence is obvious, in the Pensieri, notably in the use of the principle of variation according to the so-called “cyclic principle”; on the other hand we know that Nigetti had his favourite pupil Casini “memorize” “all music” created by the most important ferrarese – “organist in San Pietro in Rome” –. The Frescobaldi pattern appears at once through the choice of subjects clearly inspired by the vocal and “ricercare” tradition as well as in the limited extent of the pattern within which the 4 voices move, the latter being a peculiar feature of keyboard ricercare and of a vocal conception that can be traced back to the Palestrinian archetype. The expressive liking for chromatism (Tenth Pensiero) and for “pathetic” intervals (Eighth Pensiero) should be noted, as well as all devices of counterpoint (the so-called “imitazione d’inganno” excepted), such as diminution (notably in second and third movements), augmentation, inversion (Pensieri second, sixth, eleventh, twelfth), the so-called “hexachordal imitation” (Second Pensiero). All of this with a view to developing the whole composition by coherent treatment and processing of the initial subject. Milton Setter has noticed, especially in Second and Third movements, the influence of rhythmic aspects peculiar to the dance music of the French Court, and more generally – for its “cyclic structure” – some parallelisms with the seventeenth century Sonata. The harmonic language of some Pensieri and the pursuit of a limpid melodic behaviour are “modern” features present through the whole of Casini’s work, a monument to the “ancient” style in which Domenico Zipoli’s expressive peculiarities can be discerned.