The European dragon is a legendary creature in folklore and mythology among the overlapping
cultures of Europe.
The Roman poet Virgil in his poem Culex lines 163–201, describing a shepherd battling a big constricting snake, calls it "serpens" and also "draco", showing that in his time the two words probably could mean the same thing.
In and after the early Middle Ages, the European dragon is typically depicted as a large, fire-breathing, scaly, horned, lizard-like creature; the creature also has leathery, bat-like wings, four legs, and a long, muscular prehensile tail. Some depictions show dragons with one or more of: feathered wings, crests, ear frills, fiery manes, ivory spikes running down its spine, and various exotic decorations.
In folktales, dragon's blood often contains unique powers, keeping them alive for longer or giving them poisonous or acidic properties. The typical dragon in Christian culture protects a cavern or castle filled with gold and treasure. An evil dragon is often associated with a great hero who tries to slay it, and a good one is said to give support or wise advice.
Though a winged creature, the dragon is generally to be found in its underground lair, a cave that identifies it as an ancient creature of earth.
Dragon#EtymologyDragon § Etymology
Dragons in Greek mythology
Roman dragons developed from serpentine Greek ones, combined with the dragons of the Near East, in the context of the hybrid Greek/Eastern Hellenistic culture. From Babylon, the muš-ḫuššu was a classic representation of a Near Eastern dragon. St John's Book of Revelation—Greek literature, not Roman—describes Satan as "a great dragon, flaming red, with seven heads and ten horns". Much of St John's literary inspiration is late Hebrew and Greek, but his dragon is more likely to have symbolized the dragons from the Near East.