Nun komm der Heiden Heiland

Dieterich Buxtehude c. 1637/39 – 1707) was a Danish-German organist and composer of the Baroque period. His organ works represent a central part of the standard organ repertoire and are frequently performed at recitals and in church services. He composed in a wide variety of vocal and instrumental idioms, and his style strongly influenced many composers, including Johann Sebastian Bach. Today, Buxtehude is considered one of the most important composers in Germany of the mid-Baroque.
His post in the free Imperial city of Lübeck afforded him considerable latitude in his musical career, and his autonomy was a model for the careers of later Baroque masters such as George Frideric Handel, Johann Mattheson, Georg Philipp Telemann and Johann Sebastian Bach.

There are over 40 surviving chorale settings by Buxtehude, and they constitute the most important contributions to the genre in the 17th century. His settings include chorale variations, chorale ricercares, chorale fantasias and chorale preludes. Buxtehude's principal contributions to the organ chorale are his 30 short chorale preludes. The chorale preludes are usually four-part cantus firmus settings of one stanza of the chorale; the melody is presented in an elaborately ornamented version in the upper voice, the three lower parts engage in some form of counterpoint (not necessarily imitative). Most of Buxtehude's chorale settings are in this form.

I played it twice: once with the cantus firmus on the Positif Sesquialtera and the second time on the Hauptwerk Cornet.