Friedrich Wilhelm Marpurg (21 November 1718 – 22 May 1795) was a German music critic, music theorist and composer. He was friendly and active with many figures of the Enlightenment of the 18th century. Life Little is known of Marpurg's early life. According to various sources, he studied "philosophy" and music. It is clear that he enjoyed a strong education and was friendly with various leading figures of the Enlightenment, including Winckelmann and Lessing. In 1746, he travelled to Paris as the secretary for a General named either Rothenberg or Bodenberg. There, he became acquainted with intellectuals including the writer and philosopher Voltaire, the mathematician d'Alembert and the composer Jean-Philippe Rameau. After 1746, he returned to Berlin where he was more or less independent. Marpurg's offer to write exclusively for Breitkopf & Härtel was declined by the firm in 1757. In 1760, he received an appointment to the Royal Prussian Lotteries, whose director he became in 1763, receiving the title of War Councillor. His son, Johann Friedrich Marpurg, who later became a celebrated violinist, was born in 1766. Marpurg's quarrelsome disposition and his enthusiasm for public polemics made him many enemies. Contemporaries also described him, however, as courteous and open-hearted. Marpurg is most likely at the source of a two-centuries misunderstanding that J. S. Bach would have been using the equal temperament for the performance of "Das Wohltemperirte Clavier", because of his publication "Versuch über die musikalische Temperatur", 1776, This misunderstanding was only much later first challenged by Robert Holford Bosanquet in "An Elementary Treatise on Musical Intervals and Temperament" 1876, pp. 29–30, but this position did not acquire fame. The above position of Bosanquet, that a distinction should be made between "well temperament" and "equal temperament" was rediscovered by H. Kelletat, and thoroughly defended and analysed historically in "Zur musikalischen Temperatur", 1960, especially p. 32. Thanks to this publication by H. Kelletat, almost all musicologists subscribe to this distinction nowadays. Works Marpurg published the bulk of his writings on music between 1750 and 1763. After he had attained his lottery position in 1763, he penned two works on this topic but continued to write on wider areas of music. One of the first (and most influential) works of Marpurg was his tract on the Fugue (1753) which is considered one of the oldest sources for the performance practice of J.S. Bach's Art of the Fugue. His Handbuch bey dem