On literary evidence:
There are many extraordinary tales from antiquity, including women with snakes for hair, creatures whose gaze turns you to stone, creatures with equine bodies and human torsos, many accounts of people rising from the dead, lots of tales of magic, and numerous accounts of physical encounters with fantastic beings. Ancient people were a superstitious, scientifically primitive lot, and believed in many things that today we know are silly. I find it bizarre that so many people see nothing suspicious about the extraordinary or supernatural claims of the bible, yet don’t hesitate to express disbelief in equally well documented claims of minotaurs, basilisks, and wizards.
hat tip to Pharyngula and its quote machine