In Mesopotamian mythology, Tiamat is portrayed as a primordial sea dragon in the Enūma Eliš.
The Enūma Eliš is a Babylonian creation epic preserved on clay tablets and generally dated to the late second millennium BCE. Tiamat represents the salt sea, while her companion Apsu represents fresh water. Their mingling produces successive generations of gods, but conflict eventually develops between the older and younger divine powers.
After Apsu is killed, Tiamat creates a host of monsters and appoints Kingu as their leader. The young god Marduk agrees to fight her on the condition that he become chief among the gods if victorious. He defeats Tiamat with a storm weapon, then splits her body and uses it to form parts of the ordered cosmos. Her defeat establishes Marduk’s supremacy.
Tiamat is often called a dragon in modern summaries, but the epic’s descriptions also present her as a vast serpentine or monstrous sea being. She should not be confused with Apsu, her watery counterpart, or with later Christian dragon symbolism.