As such, this post is largely a personal take on the matter. It lists my own views of who’s who and thus the ideas that preside over my sacra privata. To some extent, they are a synthesis of the information drawn from the past, trying to make sense of over one thousand years of traditions. No doubt the ancient Romans did something of the sort when confronted with practices whose original meaning they could no longer recall, as seen in the works of antiquaries on the religions and History of Rome.
Lar Familiaris and the Lares
The Lar Familiaris is the guardian spirit of a household. It may be the first in the line of ancestors, human or divine, or a numen who at some point became attached to a particular family and watches over its members, adoptive or blood ones. When relatives die and are invited to remain part of daily life, they continue to be under the protection of the Lar Familiaris and become Lares. In my household, this includes our pets, who even attend our religious ceremonies: our dogs, for instance, join us in the living room as we make offerings to Janus and other gods during New Year. Thus for me, the family Lares are the same as the Di Parentes or Divine Ancestors, who may be a specific group of the broader Manes.
Gods can sometimes be part of the lot, either as divine ancestors or deities connected to the household and therefore given a place in the Lararium. Venus could be an example, in the case of the Julii in ancient Rome, or maybe Jupiter as a father figure or a guardian of the home, much like Zeus, as explained by Apollodorosh here. Another option, more personal, is the Norse god Ingui: He’s connected with the ancestors and ‘freyr’ simply means ‘lord’ (see here), which in Latin would link Him to the household (domus) and the master of the house (dominus). And since today the governing of the home is shared by the couple, His sister Freya (domina) can accompany Him in that function.
This is an innovation of mine born out of the inclusion of historical figures in my household cult (as mentioned here). They are not blood relatives, but rather adoptive ancestors in a broader sense, as founding fathers or heroes of the country or community in which I was born and raised (the Patria or Fatherland). They can be kings, military leaders, explorers, scholars, and humanists whose genii are worshipped on their birthdays or, if the day of birth is unknown, at the anniversary of a defining moment in their lives.
The Penates are the spirits of the pantry. Or at least that’s a popular interpretation of their name (from Latin penus). As such, they are the housewights proper or the genii loci of a dwelling. They may have different origins: spirits of the place where the building was erected, deceased animals or people who remained friendly and attached to the site, spirits that may have moved from elsewhere for some reason. As a goddess of the hearth and home, Vesta is probably the best connected deity to Them, though this may be just me and She may just as easily be linked to the family Lares. However, since She’s a goddess of fire and most of us don’t have fireplaces, in modern-day life the closest thing to a hearth is usually in the kitchen, which is normally close to the pantry, and that may link Vesta to the Penates. The family Lares, on the other hand, would have a place of honour in or near the living room. Unsurprisingly, today’s common layout in urban dwellings can be a determining factor in the structure of household religion.
They may be an early expansion of the ancestors’ spirits, either by watching over the street right in front of the home or the paths inside the family property. Or it may derive from the practice of erecting tombs along the roads, thereby turning the dead into their guardians. In any case, I view Them as a type of genii loci of the pathways and, like the Penates, they may have diverse origins, including victims of road accidents whose spirits remained attached to the place.
So… when do you worship Them?
Festive dates naturally vary depending on the recipients and personal or family practices. Traditionally, the family Lares are honoured at least three times every month, on the Calends, Nones, and Ides. There’s also the Parentalia on February 13, extending all the way to the 21 and 22, with the Caristia. You may want to add the birthdays of especially loved ancestors and none of this excludes daily honours to Them, as well as to the Penates. I haven’t found a traditional date for an ancient Rome festival for the Lares Viales, so I created the Vialia in Their honour and Mercury’s, on January 4, asking Them to keep the roads safe during the starting year.