Domestic pets, and all those things which help to endear home. The Romans had household gods called pe-na'-tes, who were supposed to preside over their private dwellings. Of these pe-na'-tes some were called lares, the special genii or angels of the family. One was Vest'a, whose office was to preserve domestic unity. Jupiter and Juno were also among the pe-na'-tes. The modern use of the term is a playful adaptation.
“Bearing a nation with all its household gods into exile.”
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894