I, vaguely, recall reading about a Roman legion being involved in a fight with a dragon. They also, iirc, sent the skin back to Rome as proof.
Edited to add:
Ha! found something.
https://answersingenesis.org/dinosau...ind-the-tales/
The Roman historian Cassius Dio recounted how a Roman army once killed a dragon. The original fragment from Book 11 of his Roman History, now lost, was repeated by John of Damascus (AD ~676–749), in his book On Dragons and Ghosts: “One day, when Regulus, a Roman consul, was fighting against Carthage, a dragon suddenly crept up and settled behind the wall of the Roman army. The Romans killed it by order of Regulus, skinned it and sent the hide to the Roman senate. When the dragon’s hide, as Dio says, was measured by order of the senate, it happened to be, amazingly, one hundred and twenty feet long, and the thickness was fitting to the length.”
That's not to an academic certainty, but it's on the internet so it must be true.
Rome fights dragons, therefore, dragons should be in the game.