One of the classical protective images adapted by Christians was the foot, a symbol of good health and healing. These lamps were lit by an oil-soaked wick, inserted through the hole beside the foot’s big toe.
Round flat hanging lamps, or polycandela, were lit by oil-filled glass vessels hung from the round holes in their designs. Paul the Silentiary in 563 described the effect of huge hanging lamps that lit the great church of Hagia Sophia in Constantinople: “Thus is everything clothed in beauty…no words are sufficient to describe the illumination in the evening: you might say that some nocturnal sun filled the majestic church with light.”
[ John J. Klejman, New York (sold 1962)]
The Metropolitan Museum of Art. "Ninety-Second Annual Report of the Trustees of The Metropolitan Museum of Art for the Fiscal Year 1961-1962." The Metropolitan Museum of Art Bulletin, n.s., 21, no. 2 (October 1962). p. 79.
Wadsworth Atheneum Museum of Art. Let There Be Light. Hartford, CT: Atheneum, 1964. no. 9, p. 18.
Ostoia, Vera K. The Middle Ages: Treasures from the Cloisters and the Metropolitan Museum of Art. Los Angeles: Los Angeles County Museum of Art, 1969. no. 19, pp. 49, 253.
Bouras, Laskarina, and Maria G. Parani. Lighting in Early Byzantium. Washington, D.C.: Dumbarton Oaks Research Library and Collection, 2008. no. 4, pp. 44-45.