Of the German poem in its original form entitled Isengrînes nôt (Isengrin's trouble), only a few fragments are preserved in a mutilated manuscript discovered in 1839 in the Hessian town of Melsungen.
A complete version made by an unknown hand in the thirteenth century has been preserved in two manuscripts, one at Heidelberg and one belonging to the archiepiscopal library of Kalocsa.
In the end he poisons the lion, his benefactor, and the poem closes with a reflection on the success attending craft and falsehood while honesty goes unrewarded.
The story is told in a plain, straightforward manner; compared with the French model the German poem shows abbreviations as well as additions, so that it is not a mere translation.
The complete poem (from the Heidelberg manuscript) was edited by Jacob Grimm under the title Reinhart Fuchs (Berlin, 1834), and together with the older fragments by K. Reissenberger in Paul's Altdeutsche Textbibliothek, VII (Halle, 1886).