Not sure if I can call this knowledge since I don’t know if it’s true, but I think I identified a couple of women from the 8th century CE who are mentioned in some Irish annals as actually being the same person. As far as I know there’s next to no discussion of these women on the internet and there are basically no historical records of them, at least. So I guess if I’m right it’s very obscure?
The women in question are Eithne ingen Bresail Bregh and Eithne ingen Cinadhon (and possibly also the legendary Eithne mother of Tuathal Techtmar)
It’s about as close to a random person as you can get while still being recorded. They were royalty, but the two real ones get literally a sentence each at max