The slaves of a private Roman were divided between the familia rustica and the familia urbana.
At the head of the familia rustica was the villicus, himself a slave, with the wife who was given him at once to aid him and to bind him to his duties.
Cato, Varro and Columella all agree that slave labour was to be preferred to free except in unhealthy regions and for large occasional operations, which probably transcended the capacity of the permanent familia rustica.
This is indeed an exaggeration; the colonatus was not an oppressive system; it afforded real security against unreasonable demands and wanton disturbance, and it was a great advance on the system of the familia rustica.
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.