they provide a picture of individuals, some in detail
they present the different groups which will be the ancestors of the Romans
the very naming of some of the places, e.g. Tibur and Praeneste, flourishing in Virgil's time, perhaps were intended to inspire patriotism and unity under the peace of Augustus
the last person to be mention in book 7 is Camilla
she provides a contrast to the warriors who have gone before, and the description of her serves as an introduction to her appearance in book 11