The various candidates for the supposedly historical Robin Hood have only tenuous documentation (or non-existent) and lived over a period of two or three centuries. He’s probably a literary invention, which isn’t to say that there were no rural gangs of outlaw robbers operating in medieval England. :’) If there hadn’t been, poof, no Magna Carta. ;’)
Of course I have no documentation at all for my ancestors who lived in England in the 14th century, but I'm pretty sure they existed. I exist, after all.
Maybe we should be inventing some outlaw gangs of robbers of our own. I have a feeling we might need another Magna Carta soon.