Dragons have been a recurring theme in Human Mythology for countless generations. They are very ancient tales, and also very wide spread and trans cultural. Throughout Europe and the far east we have dragon legends. That Dragon tales appear throughout recorded history and in nearly every culture is undeniable. The origins of these tales are muted by time. Some may well be simply fairy tales but many may also be primal memories of a time when Dragons and Men coexisted. As per conventional Modern science man and dinosaur / dragon never co-existed - accumulative mounting evidence seems to indicate that perhaps this hypothesis is in dire need of re-evaluation. See: Dinosaurs and Dragons | 
