Lamp 5th-6th century Small earthenware lamps made from double molds were the most commonly used source of light in daily Coptic life. A wick produced from plant fiber or linen fabric was placed in a reservoir filled with oil, generally castor or sesame oil, and illuminated. The disc of this lamp is decorated with a chi-rho monogram, consisting of the superimposed capital Greek letters chi (X) and rho (P), the first two letters of Christ in Greek. The pearled monogram is reversed and surrounded by an alternating border of chevrons and quatrefoils.Christian symbols such as this monogram were thought to offer protection for the lamps owner.. Lamp 447037