Catholics United for the Faith gave us permission to reprint this handy guide on the history and symbolism of icons.
What are icons? In Eastern Christian heritage, icons are sacred images of Christ, Mary, and the saints, or of events in salvation history such as the Nativity or the Crucifixion. The very word "icon" comes from the Greek word for "image."
To people unfamiliar with icons, including many Western Christians, icons may initially seem weird, unappealing, or even disturbing. They don't look quite "right." Their silence and stillness is demanding, untame, and even terrifying. But with education and experience, people grow to appreciate and love them.
Icons are more than decorative art or educational illustrations. Icons are "theology in color." An icon is a place to receive grace through faith, a sacramental: Its purpose is to transport us into a transfigured world, to plant that transfigured world within us, to bring us face-to-face with a living presence and change us (cf. Catechism of the Catholic Church, nos. 1667-1679).
Iconography is rooted in the Incarnation. St. Paul wrote that Christ "is the image [literally, icon] of the invisible God" (Col. 1:15). "In former times," wrote St. John of Damascus, "God, who is without form or body, could never be depicted. But now when God is seen in the flesh conversing with men, I make an image of the God whom I see" (cf. Catechism, nos. 1159-1162).