''' is a musical setting of the biblical canticle Magnificat. It is scored for five vocal parts (two sopranos, alto, tenor and bass), and a Baroque orchestra including trumpets and timpani. It is the first major liturgical composition on a Latin text by Bach.
In 1723, after taking up his post as Thomaskantor in Leipzig, Bach set the text of the Magnificat in a twelve movement composition in the key of E-flat major. For a performance at Christmas he inserted four hymns (laudes) related to that feast. This version, including the Christmas interpolations, was given the number BWV 243a in the catalogue of Bach's works.
For the feast of Visitation of 1733, Bach produced a new version of his Latin Magnificat, without the Christmas hymns: instrumentation of some movements was altered or expanded, and the key changed from E-flat major to D major, for performance reasons of the trumpet parts. This version of Bach's Magnificat is known as BWV 243.
After publication of both versions in the 19th century, the second became the standard for performance. It is one of Bach's most popular vocal works.