Many of the writers of Aeneas' day were consumed with a passion for their country. One example is Livy, who in my humble opinion, is still one of the greatest historians to ever write. Getting back to the Aeneid, Virgil as an author sought to glorify Rome and to remind the people of the origins of their empire. As I have said, it IS propaganda. But propaganda can teach.
Propaganda can inform.
Propaganda can be pleasatn. And most of all propaganda can be an epic.