While the interval between the composition of the Prelude and of the Fugue from J.S. Bach's Prelude and Fugue for organ in C minor, BWV 546 may not be as great as the interval between the composition of the Prelude and the Fugue from BWV 562 (the Prelude of that work having likely been written sometime during the 1710s but the Fugue possibly as late as 1745), they are nevertheless hardly temporal bedfellows. The Fugue of BWV 546 seems to be the earlier of the two halves (it is a work from Bach's Weimar days [1708 - 1717]), while the Prelude came later (from his Leipzig days, 1723 and following). Bach's reasons for choosing to return to a finished, self-standing composition like the Fugue of BWV 546 so many years after and then to add to it may well have been ones of a purely internal nature, though one can't omit the possibility that some practical requirement, a pressing need for a fresh prelude and fugue during a particularly busy time, induced him to take up an old fugue and provide it with a new introductory piece. After so long, it can never be known; but one can safely proclaim that the Prelude is easily one of Bach's most imposing organ preludes.