Icon of Archangel Gabriel. One of four panels from a set of the Great Deisis icons from a sanctuary screen, Sinai
The word "icon" derives from the Greek "eikon" meaning any image or representation, but the word usually is restricted to a religious image. Although the word "icon" applies to all kinds of religious images -- those painted on wooden panels (icons proper), on walls (frescoes), those fashioned from small glass tesserae (mosaics) or carved in stone, metal or ivory -- the term is used most often with paintings on wood.
Icon of Archangel Michael, 14th century
The first Christian images appeared around the 3rd century. Perhaps for the first 200 years of its existence, Christianity was influenced by the Old Testament 2nd Commandment, "Thou shall not make unto thee any graven images" (Exodus 20:4).
A Russian Icon of an Archangel also called The Archangel with the Golden Hair from the Kiev School, mid to late 12th century
"When Christians turned to promote their religion, they found many examples in the earlier art of religions in the art of the Roman Empire. For their images, they incorporated various elements from a number of sources: from Hellenic art they borrowed gracefulness & clarity of composition; from the Roman art they took the hierarchical placement of figures & symmetry of design; from Syrian art they took dynamic movements & energy of the represented characters; and from Egyptian funeral portraits they borrowed large almond-shaped eyes, long, thin noses, & small mouths. By the time Christianity became the official religion of the Byzantine Empire (313), the iconography was developing vigorously & the basic compositional schemes were well established." (From Alexander Boguslawski)
Icon Russian Icon. Archangel Michael. 14th century. From Novgorod.
The first icons were brought to Russia from the Byzantine Empire & from Bulgaria, which became an intermediary between Constantinople & Kiev, supplying newly Christianized states with books, icons, & liturgical objects necessary for the celebration of the Christian mass.
Icon Ukranian of Archangel Michael
Angel in White, painted in 1230 at the Mileseva Monastery, Serbia
Icon of Archangel Michael
Orthodox Christian Church Of Christ The Saviour
Icon of Archangel Gabriel, 1387–1395 Byzantine
Russian Icon of an Angel
Andrei Rublev (Russian artist, (c 1360-1430) The Old Testament Trinity. Detail. c. 1410