Eastern Orthodox Icons painted in Byzantine Style, usually on wood panels, in either egg tempera or oil with a gold leaf or silver leaf  background,
Icons have their origins in the earliest period of Christianity.
The word eikon (icon - "image" Matthew 22:20) is found in the New Testament as well, used there to mean portrait Christian paintings can be found even in the oldest churches, the catacomb churches
Icons instruct the viewers in matters regarding the Christian faith, so their role isn't purely decorative, but educative as well. Their spiritual dimension can uplift the viewer to a higher plane of consciousness and feeling, as St. John of Damascus said: "we are led by perceptible Icons to the contemplation of the divine and spiritual".