I never said "prophet Dragon". now please continue. I am the type who would rather admit I am incorrect and learn than continue on in error. so continue and explain my error
The name of the hill, Mons Vaticanus, is a Latin translation of what is believed to have been an Etruscan city(Vatica, Vaticum, something like that), and has no relation to the Latin 'Vates' which means "divining" or "prophecy". The 'can', which you stated meant serpent or dragon, is also entirely wrong. There are a multitude of words in Latin for snakes & dragons, but 'can' is not one of them. In fact 'can' is not a word in Latin at all.
The idea that 'Vaticus' means 'divination/prophecy' is a Roman folk-etymology of sorts, where they themselves were connecting it to their own word Vates. Or basically, it's taking words that look similar and suggesting they came from the same source. This is not unlike people who think 'sheriff' and 'shariff' also share a recent common ancestor. They look similar, sound similar and do have
somewhat similar meanings, but there is no connection between them beyond being words.