The Heldenbuch-Prosa assembles an enormous amount of material in a somewhat haphazard fashion to explain the world of the heroic poems. Some of the material in the "Heldenbuch-Prosa" is not to be found in the narratives in the book or in other surviving material; some has parallels in the Thidrekssaga, but the compiler cannot have been familiar with that text. This suggests that he was also drawing on oral traditions, as well as perhaps as on his own invention, in order to make coherent sense of the material. Although the Nibelungenlied is not included in the Strassburg Heldenbuch or its printed version (it "is" found in the Ambraser Heldenbuch and Lienhart Scheubel's Heldenbuch), the "Heldenbuch-Prosa" provides evidence of the persistence of an oral tradition in existence alongside a well-known written text.