The origins of the Chaoskampf myth most likely lie in the Proto-Indo-European religion whose descendants almost all feature some variation of the story of a storm god fighting a sea serpent representing the clash between the forces of order and chaos. Early work by German academics in comparative mythology popularized translating the mythological sea serpent as a "dragon." Indo-European examples of this mythic trope include Thor vs. Jörmungandr (Norse), Tarhunt vs. Illuyanka (Hittite), Indra vs. Vritra (Vedic), Θraētaona vs. Aži Dahāka (Zorastrian), and Zeus vs. Typhon (Greek) among others.
This myth was ultimately transmitted into the religions of the Ancient Near East (most of which belong to the Afro-Asiatic language family) most likely initially through interaction with Hittite speaking peoples into Syria and the Fertile Crescent. The myth was most likely then integrated into early Sumerian and Akkadian myths, such as the trials of Ninurta, before being disseminated into the rest of the Ancient Near East. Examples of the storm god vs. sea serpent trope in the Ancient Near East can be seen with Baʿal vs. Yam (Canaanite), Marduk vs. Tiamat (Babylonian), and Yahweh vs. Leviathan (Jewish) among others.
There is also evidence to suggest the possible transmission of this myth as far east as Japan and Shintoism as depicted in the story of Susanoo vs. Yamata no Orochi. The exact route of this particular transmission is unknown.
The Chaoskampf would eventually be inherited by descendants of these ancient religions, perhaps most notably by Christianity. Examples include the story of Saint George and the Dragon (most probably descended from the Slavic branch of Indo-European and stories such as Dobrynya Nikitich vs. Zmey Gorynych) as well as depictions of Christ and/or Saint Michael vs. the Devil (as seen in the Book of Revelation among other places and probably related to the Yahweh vs. Leviathan and later Gabriel vs. Rahab stories of Jewish mythology). More abstractly, some aspects of the narrative appear in the crucifixion story of Jesus found in the gospels.
Read more about this topic: Chaos (cosmogony)