In Mesopotamian mythology, Tiamat is the dragon-like primordial being slain by Marduk in the Babylonian creation myth.
The story appears in the Enūma Eliš, a Babylonian epic preserved on clay tablets. Tiamat represents the saltwater sea, while her counterpart Apsu represents fresh water. Their mingling produces generations of gods, but conflict eventually leads Tiamat to create powerful monsters and prepare for war against the younger gods.
Marduk, the patron deity of Babylon, agrees to fight Tiamat on the condition that the gods grant him supreme authority. He defeats her with weapons including winds and an arrow, then splits her body. The epic uses her divided body to organize the cosmos, including the heavens and the earth.
Tiamat is often called a goddess, sea, or dragon in modern summaries, but these descriptions simplify a complex ancient text. The myth does not present her exactly like a medieval European dragon. Also, this is distinct from identifying Tiamat as the primordial sea dragon in the earlier excluded wording: here the question focuses on her defeat by Marduk.