probably not like we know them today, spitting fire and what not, but there might have been something close to it
Yes, they were called dinosaurs, and, as has alreadfy been pointed out a few times, dino bones having been found by people many hundreds of years ago are what led to the myths about dragons. And as far as the fire breathing, that is only one of the many different cultural interpretations of dragons, not all dragons were portrayed as fire breathers.