Although most ancient roman lamps were used for providing light in the home, oil lamps were also used for religious purposes in temples, and also in public buildings.
Roman lamps were primarily oil based lamps made from clay or ceramic designed to produce a continual source of light and more light than a candle.
While the Ancient Egyptians used castor oil to fuel their lamps the Romans largely used olive oil and sometimes, whale oil.
Lamps were usually placed on lamp standards, fastened to the wall or placed in niches on the wall. The Romans used clay, stone or plaster molds on a large scale until as late as the eighth century. Two molds were used to cast a lamp, one for the upper part and one for the bottom.
Early Roman period lamps had a wide base, a narrow shoulder and no handle and were often elaborately decorated. Lamps made during the later Roman period had a smaller base and a wider shoulder. Between the first and the third centuries it's believed lamps were made in factories in the south of Gaul and the north of Italy for export to all the Roman provinces.
Early Roman lamps were often round with different types of nozzles and a closed body with a central disc, and were not always decorated. Later Roman lamps were of different types, some with many nozzles, they were often brightly decorated. Some lamps had molded reliefs of gladiators and scenes of eroticism.
Oil lamps had a pouring hole on what is known as the shoulder where fuel is poured into the lamp. There is also a wick hole and nozzle; this may simply be another hole in the lamp or a longish nozzle. Some lamp nozzles had a groove that runs from the pouring hole to draw back any oil that oozes from the wick.
Some oil lamps had a handle. Most handles are small and ring shaped with a flat piece on the top so that the lamp can be held between thumb and forefinger. Lamp handles may also be crescent or triangular shaped, and lamps without a handle usually have a longer nozzle. Some lamps have what is known as a lug, an extra piece that stands out diagonally from the edge of the lamp; this is sometimes used as a small handle on which to rest the thumb.
Oil lamps had a fuel chamber, or fuel reservoir, the inside of the lamp, the usual size of the chamber of a terracotta lamp is around 22cc.
Lamps also had a wick that extended over the nozzle into the fuel chamber, some lamps have more than one nozzle, but oil consumption increases with the number of nozzles. The wick was made either of flax, linen, tow, rush or papyrus, thinner wicks burn the oil more slowly than a thicker one.