Fuga supra "Vom Himmel hoch da komm ich her"

Today's 1st Advent heralds the Christmas season. I am taking this as an opportunity to present to you the fugue I have just completed for 5 voices on the chorale melody "Vom Himmel hoch da komm ich her"!

It is a homage to the greatest master in music history. It is composed entirely in his style, very dense and relatively strict in the development. I have included the notes in which I mark the respective parts of the fuga, such as inversion, cancer, augmentation, etc., with letters.
The coda sounds with the full organ and is harmonically oriented to the individual letters of B-A-C-H. B-flat major, A-major, C-major and B-major as the dominant to the third-related E-minor alternate, connected with each other by short modulations.

Vom Himmel hoch, da komm ich her is a German-language Christmas carol by Martin Luther. The text was written around 1533/34 in Wittenberg and published there in 1535, followed by the publication of the melody in Leipzig in 1539. It is one of Luther's most famous song creations.

Martin Luther created songs for all Christian festivals, more than thirty in all. According to legend,[1] he composed this well-known Christmas carol in 1533 or 1534[2] for his own children's Christmas presents. Originally, he subordinated the text, which consists of 15 stanzas, to the minstrel's song Ich kumm auß frembden landen her und bring euch vil der newen mär as a spiritual counterfactual.[3] The song appeared in this form in the Wittenberg Klugschen Gesangbuch of 1535.[4] Later, Luther composed the chorale melody for it himself, which was first printed in 1539 and to which the song has been sung ever since. In 1555, the text was supplemented by another verse from the pen of Valentin Triller, pastor of Panthenau.

Johann Sebastian Bach used the melody for three chorales in his Christmas Oratorio: Ach, mein herzliebes Jesulein, Schaut hin, dort liegt im finstern Stall, Wir singen dir in deinem Heer.