Johann Sebastian Bach composed his six legendary Brandenburg Concertos while serving as Kapellmeister in Köthen, Germany, offering each as a dazzling showcase for a variety of ensembles. The Fourth Concerto, seen here in this clip, features solo violin and two flutes (in Bach's time, recorders) backed by a string ensemble. The instrumental palette was highly unusual for the time—representative of the spirit of inventiveness that runs through all of the concertos. This 2015 CMS performance from A