Dinosaurs were not around during the period in question, but their fossils were, as were the crocodilians and large monitor lizards. So if dragons are based on

Dinosaurs were not around during the period in question, but their fossils were, as were the crocodilians and large monitor lizards. So if dragons are based on a real thing, I prefer one of those things. But I also think it's a mistake to discount the imaginations and creativity of previous generations. They might simply have imagined a scaled up garden lizard, adding fire-breathing at some point along the way.