One problem with history that goes way back is lack of documentation. We didn't always have writing, and even when we did, records could be destroyed by war, natural disasters, and even neglect. Oral histories become distorted or embellished over time. That applies to many historical figures that are now considered fiction, even if they were inspired by someone at some time who really existed. The biggest example is King Arthur, who may or may not have been a real person, but historians believe he wasn't a king and most likely wasn't named Arthur. He is just one in a long line of folklore tales that were told as factual or fictional depending on when the story was told or who told it.
An example from the list is William Tell. The story of Tell successfully shooting an apple off the top of his son's head, under pressure of course, is important in the story of the founding of Switzerland in the 14th century. But Tell didn't appear in the literature until more than a century after the events supposedly took place, and some points of the story are contradictory. Maybe someone greatly distorted the story, or maybe it was completely made up after the fact. Read about Tell and four other historical figures that never existed at all at Mental Floss.
(Image source: Library of Congress)
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