The Babylonians believed that before the creation of the worlds there was only the dragon goddess Tiamat and her consort Apsu. They were believed to be the creators of all the Babylonian gods and goddesses. Tiamat represented the salt ocean (chaos) and Apsu the freshwaters underground. Tiamat is viewed as a large dragon embodying the untamed forces of the world before order. It is believed that the offspring gods and goddesses of Tiamat and Apsu became too noisy for Apsu to rest. Being a young forgiving mother Tiamat does not concern herself with Apsu's complaints. Apsu and his vizer Mummu plot the destruction of the young gods and godesses.
When they find out what Apsu and Mummu have plotted for them, they decide to stand their ground. Enki the God of Magick, cast a spell on Apsu and Mummu and then kills them both. Enki retreats to build his temple in the marshes of Eridu. The temple was named after the father he had to sacrifice so that his siblings could live (E-abzu). Enki and his beloved wife seek refuge in the temple and give birth to Marduk.
Marduk was said to be born with perfect form and strength, and blessed by the gods/goddesses of the world.
Later on Tiamat is said to have grown from loving carefree mother to revengeful spouse. She is deeply shaken by the murder of her consort. As Hurbur (the underworld river and maker of all things) she creates giant snakes with venom for blood, and dragons cloaked with the radiance of gods. She gives Quingu (her champion) the tablets of destiny and gathers several fearsome creatures and demons for him to command.
The offspring of Tiamat and Apsu recruit Marduk to fight off Tiamat's army. While Quingu confuses Marduk, Tiamat tries to enspell him. They are pushed into single armed combat. Marduk ensnares Tiamat in his net using wind. Tiamat tried to swallow the wind but Marduk cut into her heart and smashed her skull.
Tiamat's body is said to have fashioned out world. Part became heaven and her eyes became the sources of the Tigris and Euphrates rivers. The destruction of Tiamat was believed to be the birth of order.
I hope you find this as fascinating as I did. Here is the website I used for my information. It seems quite accurate when cross referenced to other sites :)