The Dei Panates and the large sow

When Aeneas fled from Troy, Helenus, a son of Priam, predicted that Aeneas would build a new city at a place where a white sow would give birth to 30 piglets. When Aeneas and his Trojans arrived at the coast of Latium after a long voyage from Carthage, they were hungry and so landed on the beach to eat. Aeneas prepared to sacrifice a pregnant white sow that he had brought in his ship for this purpose, but the sow escaped and fled inland, laying down under an oak-tree (or ilex-tree) and giving birth to 30 white piglets. Because of the prophecy Aeneas knew that he should built a city here. He sacrificed the 30 piglets and erected a shrine at this place. The new city he called Lavinium referring to Lavinia, daughter of king Latinus.

However King Latinus had given his daughter Lavinia to Aeneas when she was already engaged to Thurnius the king of the Rutuli. Thurnius began a war against the Latini and the Trojans in which both he and Latinus were killed. So Aeneas became king in Latium. In the continuing wars Aeneas was also killed, his body taken away by a river. Ascanius succeeded him as king. He was able to defeat his rivals and the Latini now became stronger and more powerful. They built a new city, called Alba Longa. The name Alba Longa is said to be derived from the white sow (it actually means "long white"). On the Forum of Lavinium stood a bronze statue of the sow.

The Penates (latin "dii penates") were gods of the house and especially the hearth. They were responsible for the supply of food and drinks. When Aeneas escaped from Troy he took the Penates with him from Troy to Lavinium.

Lavinium was the home of the Sulpicia gens, so hence the allusions to the great white sow and the Penates.