The atlas's own live Wikipedia source names adventure as a theme common since the earliest days of written fiction and references ancient examples such as Heliodorus, but states no single place, era or literary tradition credited with originating adventure fiction as a genre; a specific origin point could not be attested from the source consulted (checked twice, 2026-09-13).
What would resolve this A literary-history source that names a specific work, era or tradition as adventure fiction's point of origin, distinct from merely early instances of adventure as a story theme.
OpenAdventure fiction (Wikipedia)