There's More Religion Than You Think in Bach's 'Brandenburgs'
'One of the most persistent myths about Bach is that his work is marked by a fundamental conflict between the sacred and the secular.
According to this view, Bach’s ideal appointment was his stint from 1717 to ’23 as Kapellmeister (director of music) for Prince Leopold of Anhalt-Köthen. Leopold’s court observed the Calvinist faith, a liturgically austere branch of Protestantism that prohibited elaborate music in its church services.
So here — unlike in his previous positions at the Lutheran court of Weimar and at Lutheran parishes in Arnstadt and Mühlhausen — Bach was freed from having to continually oblige the church. He could focus instead on “pure” instrumental music, like the “Brandenburg” Concertos, today’s holiday-season standbys.'>>>
https://www.nytimes.com/2018/12/20/arts/music/bach-brandenburg-concertos.html