Lares are the Roman guardian spirits of house and fields, ancient Roman deities protecting the house and the family — household gods. The Lares were worshipped in small sanctuaries or shrines, called Lararium, which could be found in every Roman house. They were placed in the atrium (the main room) or in the peristylium (a small open court) of the house. Here people offered food to the Lares on holidays. read more here.
From the Late Republican and early Imperial eras, the priestly records of the Arval Brethren and the speculative commentaries of a very small number of literate Romans attest to a Mother of the Lares (Mater Larum). Her children are invoked by the obscure, fragmentary opening to the Arval Hymn (Carmen Arvale); enos Lases iuvate ("Help us, Lares"). She is named as Maniaby Varro (116–27 BC), who believes her an originally Sabine deity. The same name is used by later Roman authors with the general sense of a bogey or "evil spirit". Much later,Macrobius (fl. AD 395–430) describes the woolen figurines hung at crossroad shrines during Compitalia as maniae, supposed as an ingenious substitution for child sacrifices to the Mater Larum, instituted by Rome's last monarch and suppressed by its first consul, L. Junius Brutus. Modern scholarship takes the Arval rites to the Mother of the Lares as typically chthonic, and the goddess herself as a dark or terrible aspect of the earth-mother, Tellus. Ovid supplies or elaborates an origin-myth for the Mater Larum as a once-loquacious nymph, Lara, whose tongue is cut out as punishment for her betrayal of Jupiter's secret amours. Lara thus becomes Muta (the speechless one). Mercury leads her to the underworld abode of the dead (ad Manes); in this place of silence she is Tacita (the silent one). En route, he impregnates her. She gives birth to twin boys as silent or speechless as she. In this context, the Lares can be understood as "manes of silence" (taciti manes).
Stories connect the Lar to the hearth, the underworld, generative powers (however embodied), nourishment, forms of divine or semi-divine ancestry and the coupling of the divine with the servile, wherein those deprived by legal or birth-status of a personal gens could serve, and be served by, the cults attached to Compitalia and Larentalia. Mommsen's contention that Lares were originally field deities is not incompatible with their role as ancestors and guardians. A rural familia relied on the productivity of their estate and its soil: around the early 2nd century BC, Plautus's Lar Familiaris protects the house, and familia as he has always done, and safeguards their secrets.
The little mythography that belongs to the Lares seems inventive and poetic. With no traditional, systematic theology to limit their development, Lares became a single but usefully nebulous type, with many functions. In Cicero's day, one's possession of domestic Lares laid moral claim of ownership and belonging to one's domicile. Festus identifies them as "gods of the underworld" (di inferi). To Flaccus, they are ancestral genii (s. genius). Apuleius considers them benevolent ancestral spirits; they belong both to the underworld and to particular places of the human world.