The lamps are typically hung on the arch of an Icon Screen (or over the top of the first tier of icons), directly over each of the major icons on the first tier, i.e. Jesus Christ, the Mother of God, the patronal saint or feast of the parish, St. John the Forerunner, and the Archangels. They may be hung similarly over any icon in the church, including the Icon Veneration Stands in the narthex. Traditionally they are fueled by oil, but can be lit with candles. They are a part of the illumination of the church, electric lights being an innovation of the 20th century. They can also be used for your personal altar or any situation where a candle would be lit for an extended period of time, a symbol that Christ is the "Light of the World" (or as we are hearing in the Presanctified Liturgy during these days, "The Light of Christ Illuminates all,"), and that the smoke takes our silent prayers to heaven.
