What system did Bach use to compose his Prelude in C Major?

Bach - being active during the Baroque period - used lots of different systems and methods for composing, depending on what type of piece he was writing. However, when it comes to his Prelude in C Major, he tends to focus on two main characteristics of the Baroque style; Harmony and Modulation. Harmony can be found in this Prelude at the points where Bach changes chords in the right-hand part - where he often moves to the subdominant or dominant chord, creating a plagal or perfect harmony. This harmony is emphasized because he keeps the root note of the root chord playing, as a pedal in the left-hand part. Bach uses modulation in a similar way, by using the cycle of fifths to modulate around the root chord of C major, including diminished, suspended, inverted and 7th chords.