TIAMAT AND MARDUK
(From Enuma Elish, the Babylonian story of creation. Dated at around 1700 BCE, but aspects of the story could go back to about 2000 BCE.)

In this story it is said that before the time of the gods and the world there was nothing but a waste of chaotic waters ruled by Apsu and Tiamat, a dragon-like creature. As time passed gods were created in hopes of bringing order to this chaos. One of the gods, Ea, slay Apsu, thus making Tiamat and her brood of monsters mad at the gods. Tiamat waged war against Ea and the other gods and was successful in stifling their efforts until Marduk was born. Marduk was the strongest and the wisest of the gods and was elected to deal with Tiamat once and for all. Upon summoning the powers of all of the other gods, Marduk went to war with Tiamat. Tiamat was no match for Marduk and all of his powers. Marduk caught her in his net and when she opened her mouth to breath fire at him, he let loose the four winds which filled her up rendering her defenseless . Marduk then speared her with a lightning bolt, split her in two and raised half of her body to create the sky and with the other half created the earth.

This is a classic example of a male deity slaying a female dragon or serpent-like monster in an attempt to replace a cooperative, "chaotic" natural order with a hierarchical, paternal, and often monotheistic system.