The entire Poetic Edda, including this prayer, survives from the medieval period in essentially one manuscript witness of real completeness, the Codex Regius, copied in Iceland around the thirteenth century from material already understood at the time to be older, and this manuscript itself disappeared from scholarly view for centuries before being rediscovered and brought to wider attention by the Icelandic bishop Brynjolfur Sveinsson in 1643, who sent it onward to the Danish royal library, which is why it carries the name Codex Regius, the king's book, today. Had this single manuscript been lost before its seventeenth century rediscovery, this prayer, along with a considerable portion of what we know of Norse mythology as an ordered poetic tradition rather than only later prose retelling, would likely not have survived in anything like this form.
A manuscript problem specific to this section compounds the uncertainty around the poem: a physical gap in the Codex Regius occurs shortly after this material, and the identity of the valkyrie speaking here, Sigrdrifa, is not securely distinguished by all scholars from Brynhild, a differently named figure central to the surrounding heroic material, since later prose sources and some modern scholars treat the two as the same character under different names while the poetic text as preserved does not settle the question outright, leaving the prayer's speaker's precise place within the wider Sigurd legend genuinely unresolved.