The windows of some of their houses were glazed with a thick kind of glass, not perfectly transparent; in others, isinglass split into thin plates was used. Perfectly transparent glass was so rare and valuable at Rome, that Nero is said to have given a sum equal to £50,000 for two cups of such glass with handles.
Houses not joined with the neighboring ones were called Insulæ, as also lodgings or houses to let. The inhabitants of rented houses or lodgings, Insularii or Inquilini.
The principal parts of a private house were the vestibulum, or court before the gate, which was ornamented towards the street with a portico extending along the entire front.
The atrium or hall, which was in the form of an oblong square, surrounded by galleries supported on pillars. It contained a hearth on which a fire was kept constantly burning, and around which were ranged the lares, or images of the ancestors of the family.
These were usually nothing more than waxen busts, and, though held in great respect, were not treated with the same veneration as the penates, or household gods, which were considered of divine origin, and were never exposed to the view of strangers, but were kept in an inner apartment, called penetralia.
The outer door was furnished with a bell: the entrance was guarded by a slave in chains: he was armed with a staff, and attended by a dog.
The houses had high sloping roofs, covered with broad tiles, and there was usually an open space in the centre to afford light to the inner apartments.
The Romans were unacquainted with the use of chimnies, and were consequently much annoyed by smoke. To remedy this, they sometimes anointed the wood of which their fuel was composed, with lees of oil.
The windows were closed with blinds of linen or plates of horn, but more generally with shutters of wood. During the time of the emperors, a species of transparent stone, cut into plates, was used for the purpose. Glass was not used for the admission of light into the apartments until towards the fifth century of the christian era.
A villa was originally a farm-house of an ordinary kind, and occupied by the industrious cultivator of the soil; but when increasing riches inspired the citizens with a taste for new pleasures, it became the abode of opulence and luxury.