Dragons?

Ever since I became a Brony I have wondered about the dragons of the MLP:FIM universe I mean we know so little about them, Where do they come from? What is their culture? how did hatching dragons eggs become tests for student pegasi? And so I have thought.....and this course of action has left me with only more Questions. I have sought out the answers through the Ponies Wiki, Pony threads, and my Brony friends and have come up with little....so....I feel as if this is a subject that needs further explanation. So I have begun to write ,something I really should do more of, A fan-fic to help explain the dragons purpose and place in the canon as well as expound upon the world of FIM.