In searching for the meaning behind the rapidlychanging time signatures, note values, and tempowords in Dieterich Buxtehude's organ praeludia, orthe logic behind Johann Sebastian Bach's timesignature revisions in his Kunst der Fuge, BWV 1080, the mostpragmatic course of action would first be to studythe music treatises written contemporary to thesewell-known musicians. But upon reading the abundantwritings on tactus and tempo permeating the musicscene for the majority of the Baroque period, itbecomes very quickly apparent that the principlesexplained therein were undeniably based on previoustheories of tactus and tempo.

In addition, many of the treatises do not presenttheories of meter and tempo in a way thorough enoughfor a modern musician to understand. In fact, thereare only two time periods that contain in-depthtreatise explanations on meter and tempo. At thebeginning of the Baroque era, there is the detaileddiscussion of tempo in Praetorius's Syntagma MusicumIII (1619), and in the third quarter of theeighteenth century, we have the lengthy discussionsby Heinrich Christoph Koch (1787), Johann AdolphScheibe (1773), and Johann Philipp Kirnberger (1776)among others. In the period between these, however,I can find no treatises that go as extensively intothe topic of tempo as those by the above authors.For example, while Nicolaus Gengenbach (1626),Wolfgang Hase (1644/1657), Johann Crüger (1660),Johann Adam Reincken (1670), Daniel Speer (1687),Georg Falck (1688), Daniel Merck (1695), FriederichErhard Niedt (1710/1700), Johann Samuel Beyer(1703), Johann Peter Sperling (1705), MartinHeinrich Fuhrmann (1706), Franz H. A. Murschhauser(1707), Johann Philipp Eisel (1738), and Joseph F.B. C. Majer (1741) offered insights into the use oftime signatures in the middle of the Baroque period,tempo relationships were stated only in vague terms.Even Wolfgang Caspar Printz (1689) and JohannMattheson (1713, 1735), while supplying moreinformation than the average treatise author, didnot come close to the depth and scope of the authorsboth at the very beginning and very end of theBaroque era.

It is possible that the reason for this paucity ofinformation in the mid-Baroque was because thetheory of tempo and meter was well understood andtherefore the necessity for its detailed explanationdid not exist.