The sources of this creature are in the European folk traditions, Greek and Middle Eastern mythologies and Oriental dragons (especially Chinese dragon which was a symbol of Emperor and the primordial principle). In Medieval art we also find two affronted dragons. It means a neutralization of adversary tendencies of alchemical sulfur and mercury. A dragon swallowing his tail is called Ouroboros and represents the eternal return or cycle, self-reflexivity. The image of Ouroboros is traced already in Ancient Egypt. Later it came to Greek philosophers. Plato described it as a first, circular, immortal and perfect creature. In Christianity Ouroboros means the limited boundaries of the material world.
Dragons were believed to be real for a long time and were present in wonder collections. It is not surprising that dinosaur fossils were taken for the bones of dragons. Besides, stuffed dragons were formed from dead rays (fish) and dried afterwards.