I've been doing a lot of reading on Homeric myth and was struck by something. Plenty of Greek kings claimed descent from Greek heroes, such as Achille's son Neoptolemus. The myths explicitly tie the fate of these characters to the Greek cities they returned to or established. But those character already survived the Trojan War, so tying their fates into your history wouldn't be too hard. In the case of Aeneas, however, I was bit confused. There's not much reason to write about a guy escaping Troy unless you have a story to tell involving what happens next, and no one in Greece would've cared enough about Rome at the time to say that Aeneas founded it. So where did the ideas that Aeneas escaped Troy and eventually founded Rome come from? Did Virgil just make it all up or was it already somewhat established?