Passacaglia and Chaconne

Two closely related forms of the Baroque era.  Each a kind of continuous variation.  There have been may futile attempts to explain the derivation and original meaning of these terms, and just as many attempts, equally futile, to make a clear distinction between them.  Actually, Baroque composers used the terms indiscriminately.

To conform with the titles of the two most famous example, those by Bach, the passacaglia is a continuous variation based on a clearly distinguishable ostinato that normally appears in the bass but that may occasionally be transferred to an upper voice.  A chaconne, on the other hand, is a continuous variation in which the "theme" is a scheme of harmonies usually treated so that the first and last chords are fixed whereas the intervening ones can be replaced by substitutes.