The Dragon
The mythical dragon is a Middle Age symbol of sin in general and Paganism in particular. The Celtic use of the word for “a chief” is the source of the legendary dragon slayer, as a knight killing a chief thereby slew a dragon.
The dragon, which appears as a guardian, as in the garden of the Hesperides, watching the tree bearing the golden apples of Hera, is also a poetic allusion to flood or inundation.
The tradition of the Python and Apollo is an instance of poetic allusion to the power of the sun drying up the overflow, as also the deliverance of the city of Rouen by St. Romanus from the dragon Gargouille (waterspout) which lived in the Seine.