No comprehensive account of Norse mythology was ever written down by those who believed in it, or if it was, those records or references to them have not survived to this day. The only accounts we do have are those compiled by Christian monks who were converting the old Norse believers, right at the end of the pagan era.

These accounts are heavily colored by the expectations and the worldview of those monks, and we do not know where the ideas that the Norse actually believed in end and where the ideas of what the monks thought religion is supposed to be begin. For example, much of the popular conception of Ragnarok is heavily influenced by Christian eschatology, instead of the original Norse beliefs. To complicate it even further, the Norse beliefs were in no way static, and as the influence of Christianity spread, the beliefs might have morphed to absorb concepts from Christianity.