Next to this comes the sanctuary of the Lares of the city, a square room with a large apse; and beyond this, as Mau proves, the small temple of Vespasian.
Amongst these must be included, at least after the time of Augustus, the Lares compitales.
This legend probably arose from the connexion of Acca Larentia, as mater Larum, with the Lares who had a part in the religious ceremonies of the Arvales.
The public Lares belonged to the state religion.
The old view that the Lares were the deified ancestors of the family has been rejected lately by Wissowa, who holds that the Lar was originally the protecting spirit of a man's lot of arable land, with a shrine at the compitum, i.e.
Its importance was revived by Augustus, who added to these Lares his own Genius, the religious personification of the empire.
The Lar familiaris has been regarded' as the embodiment of all the family dead and his cult as a consummation of ancestor-worship, but a more probable explanation regards him as one of the Lares (q.v.; numina of the fields worshipped at the compita, the places where properties marched) who had special charge of the house or possibly of the household servants (familia); for it is significant that his worship was committed to the charge of the vilica.
As Janus is in the household the numen of the door, so in the state he is the god associated with the great gate near the corner of the forum: the Penates have their analogy in the Di Penates populi Romani Quiritium by whom the magistrates take their oath on entering office, the Lar familiaris in the Lares Praestites of the community, and the Genius in the new notion of the Genius populi Romani or Genius urbis Romae.
On these occasions the Lares were crowned with garlands, and offerings of cakes and honey, wine and incense, but especially swine, were laid before them.
The whole group was called indifferently Lares or Penates.