Virgil’s

Aeneid

not only defines， through the portrayal of pius Aeneas， “pietas （piety）” as devoting wholeheartedly to one’s own parents and family， fatherland， and to the gods as well， but also presents， through the quarrel between Dido and Aeneas， another kind of piety applicable only to parents， family and the state. The former of which can be called “Aeneas’ piety”， the latter “Dido’s piety”

. A historical study shows that， from an idea in purely ethical sense to a concept in both ethical and religious sense， the Roman pietas went through a development from “Dido’s piety” at the very start to “Aeneas’ piety” at the last. As in episode of Scipio’s Dream in Cicero’s De Re Pubilica， Aeneas’ piety may be further changed into the “Paulus’ piety” with the traditional Roman gods having been replaced by a Stoic god. The pietas full of religious sense in the Aeneid， “Aeneas’ piety” or “Paulus’ piety” may it be， is not only a ritual means to end the civil wars， to promote the unity and set down a social and political order， but also the political theological basis of the imperial expansion and domination， and was therefore moulded by Virgil into a central symbol of Roman identity.