CASSIUS ADMIN NOTE: I am splitting this off from another thread (link here)so as not to divert that one. My main interest at the moment is to trace back in outline form the question of what the Epicureans and/or other ancients might have thought about this question, given the importance of the Timaeus in Greek ideas about world history and the nature of the world as a whole. Don's links may answer that question already but I think the topic is worthy of being clear so we can relate that aspect to the rest of Plato's discussion of creation and world history.
Was the entire story of Atlantis, and/or the rest of his creation story, understood by the ancients to be allegorical?
This is the source (or part of the source) of the story of Atlantis, so it's interesting for lots of reasons.
Just for the record, there was no physical place called Atlantis. It is entirely a literary invention of Plato to make a philosophical point.
While some leave open the idea that Plato may have been *inspired* by accounts of the eruption of Thera or other events, the "myth of Atlantis" is just that - a myth.
The podcast Let's Talk About Myths, Baby! did an excellent series on Atlantis: