The Chorale Preludes of Leipzig (or rather, the autograph of Leipzig, because the manuscript was found there), or even different species Eighteen chorales BWV 651-668 are a series of eighteen Chorale Preludes for organ composed by Johann Sebastian Bach in Leipzig in his last decade of life, between 1740 and 1750 from other tracks written previously in Weimar, where Bach was court organist. The work forms an encyclopedic collection of Chorale Preludes in a variety of style that takes into account the entire previous century. Together with the Orgelbüchlein, the Schübler Chorales and the third part of the Clavier-Übung, represent the epitome of sacred organ music by Bach.
Nun komm ' der Heiden Heiland, in Organo pleno, Canto fermo in Pedale, BWV 661
Under a three-voice Fugue Bach typically performed by hand, with a theme of quavers derived from angular melody, is the pedal cantus firmus; the theme of the fugue, the controsoggetto and their inversions are combined in various ways in the course of the piece.