This is a festival for honoring one's dead parents. Families gathered among the tombs of loved ones and made offerings or sacrifices of grain and wine to their souls. The Parentalia was the first of three festivals in February for appeasing the dead which started on the Ides and lasted until the 22nd. It typically fell on February 13 or 15, and was followed by the Feralia and Caristia. During this time all temples were closed, marriages were forbidden, and public officials suspended business for the duration of the festivals.
There were a few things mentioned in there, all of them having to do with Family. Parentalia: Honoring of Parents who have crossed over. Feralia: Honor spirits of the dead in general, including the restless dead who need to be driven out of a home or tricked out. The Caristia was a time to honor your family, like a family reunion. So there it is: Departed parents, all souls, living family.
Notice that the time to honor and gather with family comes right around the time the weather is once again good enough to travel. This was likely the first time extended family got together since the winter holidays.
Lupercalia has nothing really to do with this, it happens to fall during this time. In the original post, I spoke of retconing it, but it's less of a retcon and more Rome-specific whereas the Parentalia was celebrated by the Etruscans and predates Rome.
More from Nova Roma:
The Parentalia is the Roman festival for honoring one's dead parents. Families gathered amongst the tombs of loved ones and made offerings or sacrifices of grain and wine to their souls. Although the Parentalia always began with the performance of ceremonies in honor of dead parents by a Vestal Virgin, Romans basically celebrated the Parentalia at the family level. Families walked outside the city to visit the family tombs and performed private sacrifices in honor of dead kin (especially parents). The sacrifices were simple, a little wine, a little corn or bread, perhaps some votive garlands. It was a quiet, personal, reflective day, followed by a quiet reflective week or so to think about loved ones and the importance of the family.
The long name for this festival is the Parentalia Novindalia. the nine days feast. It went from the 13th through the 21st. Nine days, as I've said before, is important. Nine is the number of Mars and action. During this week I will be working a novena in memory of my family.
It's time to clean (or start!) your ancestor altar. It's time to visit the graves of loved ones in person, if possible, in thought otherwise. Whatever offerings you would bring to the grave, bring to a crossroad if you can't go to the site. And have some fun with your loved ones this week!