I was just wondering because there is the english legend of Saint george slaying a dragon and another on the Welsh flag but also a completely different one in the Chinese zodiac. Did two completely independent myths develop and evolve or was one inspired by the other?
Despite it doesn't cover dragon slaying saint, you have this very fine article https://www.reddit.com/r/AskHistorians/comments/3iarqe/do_historians_know_why_we_see_dragon_mythology_in/cufab91 from /u/AdamSC1.