Although the circle of fifths and its modulatory properties had been theorised in the sixteenth century, it was Arcangelo Corelli who imported the theory into the practical domain. Instead of using continual "perfect" fifths, a single diminished fifth kept the cycle within the diatonic realm, and thus allowed each scale degree to potentially act as a harmonic root (as opposed to being defined by its melodic resolution tendencies).
The result was that Corelli, who only wrote instrumental music, could give the sort of formal structure to instrumental music that vocal music derived from text. Thus Italian instrumental music in the 1680s exhibited a fully elaborated tonal system; pieces began and ended in the tonic key, travelled to the dominant (V), and possibly visited other keys close by on the circle of fifths. What was unique about this use of the circle of fifths was that it played a global, structural role.
The extravagance of fifth-related harmony was often counterbalanced by descending melodic sequences, which created smooth voice leading through the sevenths of thirds of the harmony. In contrast, ascending sequences allowed composers to modulate to relatively distant key areas via what we now call "secondary dominants," setting up the inevitable "unravelling" of harmonic tension via the circle of fifths.
For composers, they now had a way to create tension and release over a large structure without relying on text. Listeners came to listen to these pieces differently; the momentum created by these harmonic structures required closer attention. Their attention was rewarded in experiencing the waves of tension and release, or implication and realization, crafted by composers. Hence an important step had been taken towards instrumental music's autonomy.