To write about a character, who may be real or unreal, is a difficulty within itself. It is especially difficult when there is little no evidence or information. Historians have their own speculations. Literature and theatrical arts even have their own take on mythology. King Arthur is a mythical character. No one really knows if he is real or fake. His life is based on real historical events.
Most people know of the tale of King Arthur of England. While his legend is probably a myth, it can probably be based off the life of a real human. His story comes down to readers as folk tale, and most it follows heroic or romantic cliché. Nonetheless, much of the tale is verified by historical events and physical evidence for example, castle remains