Did Herodotus believe every story that he included in History?
No, Herodotus did not believe every story he included in his History.
Although he developed a reputation for credulity and was known for his love of a good story, he did not endorse everything he reported. Herodotus believed that his duty as a historian was to record the traditions and accounts of various peoples, regardless of how dubious they might seem.12
He was capable of critical judgment; for instance, he explicitly dismissed a story the Greeks told about the mythical hero Heracles as a "silly fable," noting that it reflected poorly on the Greeks' own critical sense. Ultimately, he combined his narrative artistry with a conscientious effort to question witnesses and discern the causes of events, even while preserving traditions he did not necessarily accept as factual.1