In Lachen, Weinen, Hoffnung schenken, which I read in November, Rabbi Eisenberg strongly recommended reading Der Rabbi von Bacherach: ein Fragment. What the library had was Die Von-Geldern-Haggadah und Heinrich Heines "Der Rabbi von Bacherach" Well, it turns out that the Haggadah is an 18th century manuscript owned by Heine's family, that he would have known as a child. Its location was lost, but now it has been traced, and this book includes full size photographs of the full document, along with Heine's 'Fragment' and several articles about the manuscript and the story. There is also a 19th century translation of the Haggadah into German, which would be useful if you were doing literary studies of Heine, but I'm not, so I skipped that. The print in this book is miniscule.

The story tells of a medieval Seder, at which two strangers arrive. Rabbi Abraham finds out during the meal that they have brought the bloody corpse of a baby to deposit under his table, He flees with his wife, the beautiful Sara. They travel to Frankfurt and join the ghetto there.

This was almost certainly deliberately left as 'a fragment'. Heine moves smoothly between the medieval setting and his own time. He depicts the various characters very well. The basic point of the story is Jewish life in the diaspora, and how the various people deal with the challenges involved. I suspect that the better you know German Jewish culture the more you would get out of it. I don't, but kept recognizing references to things I do know. This is a very carefully written text, with great depth.

It turns out that the Von-Geldern-Haggadah is probably not that useful for understanding Heine's text, but I enjoyed looking at it.
5* ( )