Let's first look some of the earlier stories about Dragons. The very first "written" stories (that we have uncovered so far) on the creation of the world is from the Sumerian civilization generally in the area we call Mesopotania. This area which later became Persia and then part of various Middle East civilization is generally found between the Tigris and Euphrates Rivers in what is now Iraq and Iran.
The actual word "dragon" comes from the Greek language much later than this time so any mundane interpretation of creatures by this name before the Greeks must be by descriptions and attributes and not by name. They were generally considered "monsters" even if they had divine attributes.
The very origins and foundations of the entire Mesopotamian culture comes from the stories, culture, and ethics of these Sumerians. The later civilizations of the Assyrians, Babylonians, Persians, and then Grecians all got much of their philosophy, cosmology, and religion from the earlier stories/ myths of the Sumerians so it behooves us to first look at these early very early stories and pay particular attention to them.

In fact so many of the stories sprout the same type of general story line that we can actually divide them into two categories; Gods versus monsters (dragons) before creation and heros versus monsters after creation. Later versions of the stories often change the names of the parties about but maintain the basic story line. Is it possible that all these stories came from a single source and was later simply adapted, adopted, and some elements changed to suit the civilization telling it? This is a possibility to be considered about these first stories. Many later dragon stories will also be changed in the same manner by different areas or countries but with the same original tale.

The earlier myths often have a god, usually a storm god or a god armed with thunder and lightning bolts, chasing a dragon that has something to do with water. Examples are almost all of the Mesopotamian stories, the Indian god Indra, both Chinese and Japanese myths, the Mayan Rain Gods, the Egyptian sea dragon/serpent Apophis and pursuer Re, and even many early Semitic stories.

From the very start Dragons were seen as guarding treasures, holding back the floods, and dispensing knowledge. They also are battled by gods or heros from the very beginning. In many cases stories from the Sumerians were borrowed and slightly changed by the preceding civilizations. These same stories were very similar in content but with the actual names of the participants changed.
The first written commentary, found on clay tablets, uses the names of Asag, a monster/dragon (sometimes named as Kur) and Ninurta, a god/hero. Later we are introduced to this same god/hero as Marduk by the Babylonians and the dragons name has been changed to Tiamet. There is some confusion here as the preserved evidence is not in good shape or complete.

In the Babylonian version called the "Enuma elish" Tiamet is one of the original pair of god and goddess at the founding of the universe. From these two all later creatures, good or bad, came into creation. This Goddess is in effect the "mother of all."

In the beginning of the tale Tiamet defends her offspring and all of creation from all the minions and forces of evil. But later, when her husband Apsu is killed, she apparently goes mad and decides to end all creation in her grief. This irrational action pits her against all the other Gods and one of her offspring, named Marduk, is talked into opposing her.

In the fight that ensues Marduk finally kills her by shooting an arrow into her mouth as she tries to swallow him. She is a shape shifter as most or all early Dragons are assumed to be so fought him in different guises. Even time seems to be effect which will come up again in the dragons versions. After the battle he uses her dragon body to form the earth and from death we have life and substance.
The first epic of the hero or human and dragon encounter is the "Epic of Gilgamesh." This we know of by clay tablets from Semitic origin. But these tablets are telling about much earlier versions of the story. Here the hero is pitted against a Dragon named Humbaba who also has shape shifting abilities. Gilgamesh with the aid of the god Shamash finally kills the Dragon but gets in trouble with those other gods who were friends with or supported the Dragon and so has a pyrrhic victory and some penalties for his action are imposed.

Not much later we find the Egyptians with a similar story of either Re the sun god or Seth the hero destroying the snake or Dragon named Apophis. Again there is much confusion and contradictions. In this story both the side of good and the side of evil have attributes of the dragon. So once again we see the idea that the winner of the contest with the dragon take on the attributes of the dragon.
The Hittites have a story of the battle of a storm god with the Dragon named Illuyankas which also has contradictions and different versions but also follows the earlier stories in general details.
Later on we get several versions from the Grecian civilization. There is the story of Zeus fighting Typhon. Typhon is described as "Up from his shoulders there grew a hundred snake heads, those of a dreaded dragon." We will deal with the relationship between snakes and dragons a little latter. But suffice for now to say they are essentially the same. And again this monster/dragon is slain by a mighty thunderbolt from Zeus.

Very similar to this is the story of Apollo and Python. Python is alternately described in different versions of the story as a giant snake or a female dragon with many coils. In any case in some versions she is killed by Apollo when the young god shoots an arrow down her throat. But in other version she is taken into his service and becomes a protected oracular serpent at Delphi. It is interesting to note that both Grecian and Romans had serpents or dragons that were kept at various temples including Delphi that were considered to have great knowledge.

It is also interesting that Hercules himself consulted the Oracle of Delphi and was directed on his "12 labors" by the advice he got their. Included in his labors were the destroying of the dragons Ladon and Hydra of the Seven heads.

A good example of another Greek hero is Perseus who instead of fighting for good versus evil killed a dragon that was about to devour the princess Andromeda in order to marry her and gain a kingdom. The dragon was sent by the god Poseidon or Neptune to avenge an insult.

Another hero dragonslayer was Jason who along with his companions the Argonauts had to overcome the unsleeping "dragon of a thousand coils" who guarded the golden fleece. In one version the dragon is ensorcelled into sleeping and they stole away unharmed with the treasure. In another Jason fought the dragon who was a sea dragon and lost the fight and so was swallowed. it was only by intersession of the god Athene that the dragon gave up her prey.

An interesting story related to Jason is that of Cadmus who later went on to be the King of Thebes. He was also given advice by the Oracle of Delphi (who was herself a dragon) that eventually led him to fight and kill a golden crested dragon at the spring of Ares. For killing this dragon Cadmus was forced to serve the god Ares for a year but was then allowed to found his city from the children of the dragons teeth.

This info was taken from a book on dragons I have,I went through the trouble of tayping it ALL out for you.

First post copied from: http://sommerland.org/ondragons/existence/theoreal.html.Well Chatz, the exact same information is available here: http://www.biopark.org/dragonhistory.html, which is a website, not a book, and can easily be copied...