Lares and penates are generally grouped together as Roman household gods, together with the virgin goddess Vesta, guardian of the domestic hearth. The lares and penates were, however, two distinct types of family guardians. It is thought that the lares were originally the spirits of a family's ancestors, watching over the good of every succeeding generation, or maybe they were the spirits that watched over a family's fields, thus ensuring continuing prosperity for that family. The lares were to be found not only among families, however, but also at other places like city crossroads and also functioned as protectors of entire neighbourhoods. In fact their domain actually extended to cover the entire state.
The penates were guardian spirits of the storeroom, the penus, which traditionally was located at the centre of the family home. As such, they symbolized abundance at the very heart of the family, and were propitiated at mealtimes and other domestic occasions.
The lares and penates, then, had a very important function in ancient Roman times. They are varieties of the domestic spirits that are to be found in many cultures all over the world - some more volatile than others.