History is not the work of any one historian. Like any academic discipline, it is an attempt to reach a consensus on what happened, why it happened, and what were the consequences,based on an understanding of known facts. Like any academic discipline, knowledge is imperfect as not all the facts can be known, and of course different people will come to different conclusions. Where enough historians can agree then something can be said to be decided, but only for now. Knowledge evolves over time as new facts emerge and new interpretations are made.

All sources are unreliable until their provenance can be established. The problem with folk history is that those provenances are usually unknown. In most cases we do not know where the story or song originated, whether the author was an eye-witness or based it on hearsay, whether details were changed to make a better story or to achieve a rhyme, or to what extent the story was altered in subsequent re-tellings. That is the very nature of folk history.

Folk history may be able to tell us a lot about a community's attitudes to something, both around the time of an event and subsequently. Whether it can be relied upon as a description of that event is very doubtful, and can probably only be known if the details can be confirmed from other sources.