21, TWV 1:1748, is Melchior Hoffmann's musical setting of a German version (Meine Seele erhebt den Herren) of the Song of Mary (Magnificat, "My soul magnifies the Lord") from the Gospel of Luke.

In the Luther Bible, the first verse of the German Magnificat reads "Meine Seele erhebt den Herren".

Among the students of Leipzig University belonging to that ensemble was Gottfried Heinrich Stölzel, who helped Hoffmann copy out performance parts of his Magnificat.

Shortly thereafter, Gerlach, who also was a singer, made a new copy of the vocal part of Hoffmann's Magnificat, with some adjustments to make it more suitable for performance.

The manuscript performance parts of the A minor Magnificat which were once owned by Breitkopf later came in the possession of the Berlin State Library (SBB).

[15] In fact, Dehn, who also assumed that the manuscript was a Bach autograph, had deliberately kept it away from the BGA editors, shipping it to Russia shortly before his death in 1858.

[4] In 1940 the British musicologist William G. Whittaker located the manuscript described by Rust in a library in Saint Petersburg (at the time known as Leningrad).

When Wolfgang Schmieder published the first edition of the Bach-Werke-Verzeichnis (BWV) in 1950, he listed the Kleines Magnificat in the catalogue's first Anhang, as No.

It was also determined that the composition in the Saint Petersburg score was identical to the anonymous Magnificat in A minor of which the Berlin State Library had the performance parts.

[1][8][9][12][13][17] In his 1958 edition of the Little Magnificat, Ermenegildo Paccagnella [it] indicated Bach as its composer, notwithstanding that this attribution was no longer supported in scholarship.