They didn't distinguish between material and mythical back then. However, they did have parables which were understood to be fictive morality tales and the origin story was not to be understood simply as a parable, but a depiction of the cosmology of a bronze age people. Biblical and traditional theism involves an active god in world events, not simply a detached symbolic god and parables. Josephus referred to various events in Genesis as real and authentic in his histories of the Jews, for instance.