I am unsure what you mean, as,
History (from Greek ἱστορία, historia, meaning "inquiry; knowledge acquired by investigation") is the study of the past. Events before the invention of writing.
mythology
a collection of myths, especially one belonging to a particular religious or cultural tradition.
myths.
"this field includes archaeology, comparative mythology, and folklore"
legend,
a traditional story sometimes popularly regarded as historical but not authenticated.
I find difficult as all the above are fictitious tales, subject to many interpretations depending on who is telling the story, and making peoples appear greater or lesser to influence others, will tell this story to others and who are then able to change it again for whatever reason they need to, then who is who and what they done to lncreas or reduce their impact in their way of lives to suit, whatever is required to improve status.
Tolkien suggests that fairy stories allow the reader to review his own world from the "perspective" of a different world. Tolkien calls this "recovery", in the sense that one's unquestioned assumptions might be recovered and changed by an outside perspective.
Tolkien begins at the beginning, by defining what a fairy tale is: A “fairy-story” is one which touches on or uses Faerie, whatever its own main purpose may be: satire, adventure, morality, fantasy.
Then te influences upon professor Tolkien was from Ireland as Interestingly here it can be seen "poll na gollum" this I think is more than coincidence. I agree with Dr. Liam Campbell. Here is something of his works.
I have explained several posts with other people here and I do not want another long drawn out discussion on this as the fact the time he spent in the Burren and really some impact in the motives to pursue this culture and the above.
Then simple matter often norse invasions of Britain, Scotland and Ireland in particular the names left upon Ireland and then the travelling to America. This goes somewhere really explains their adopted cultures into their own cultures and the effects of that other way of life and the effects on their compression of their views understanding of life they encountered.
This is fact,
The Irish do have Viking DNA and are also more prone to certain diseases, DNA tests show. Yes, the Irish do have Viking DNA and are also more prone to certain diseases, DNA tests show. I think that DNA is not subject to question?