As we say in my family, "ISH" which, being interpreted, means "It Says
Here"-and I'm referring to the notes in the big New Oxford Book of Carols"
Oxford University Press 1992:

   "Mendelssohn's music was a melody in search of a poem.  It comes from
   his four movement "Festgesang" for male chorus and brass, an occaional
   piece commissioned by the Gutenberg Festival that was held in Leipzig
   in 1840 to mark what was believed to be the 400th anniversary of the
   inention of printing.  Mendelssohn toyed with the idea of adaptation
   to a more generally useful text in a letter to his London publishers,
   but was certain that 'it will never do to sacred words'.  Wesley's
   sacred words were nevertheless soon wedded to the second movement
   (Leid-song-which is repeated as the fourth) in a curious, almost
   monorhythmic adaptation which appeared in The Congregational Psalmist
   (1858-79) produced by H.A.Allon and Dr. Gauntlett for the vast Union
   Chapel in Islington, London."

In the book am quoting from, they provide 3 organ interludes by a grandson
of Charles Wesley who was a contemporary of Mendelssohn.

This book is an invaluable source of information, but I bought it-plus
the shorter version and three of Andrew Parrott's CD including many of the
"carols" including very early ones, for the pleasure of singing along-on my
own I hasten to add.  Doll collecting stopped for a few weeks as a result.
So there you are- and all done before breakfast-you have me on one of my
hobby horses.

As a friend used to sing every time he went out in his new Vauxhall that
Christnas, "Nova!  Nova"-well, that's what it was called.  Happy Birthday
-just as a change-whenever it is-we had one last Sunday, one today and one
next Monnday.

Doris><>
(too much Famous Grouse....)