Quote Originally Posted by andrewt
Well, considering they are the Iulii and Aeneas' son is named Iulus, it's not too difficult for them to come up with an excuse to claim ancestry.
And considering that the Aeneid was written by Virgil at the time of Augustus, for Augustus, who had everything to gain by getting the Julii-Aeneas connection confirmed, we can safely confirm that it has little historical basis.
It was written in a time when Julius Ceasar was skyrocketed into a deity, so of course his ancestry had to have been equally important, and thus his ancestors (even if they were only adopted) were equally cool in the mind of the Romans.

The Aeneid is more or less just a physical manifestation of Roman envy towards written Greek history. It attempts to jump in and tag along for the ride that is the Illiad.