In Christiantity, an icon (from Greek εικων, eikon, "image") is a flat picture of Jesus Christ, Mary, or other saints. Most icons are painted in egg tempura on wood, but some are created with mosaic tiles, ivory, or other materials.
In Orthodox Christianity, icons are sacred works of art that provide inspiration and connect the worshipper with the spiritual world. The scenes depicted in icons usually relate to liturgical celebrations rather than directly to historical events.
Images and pictures of Christ and the saints were a part of earliest Christianity. Christians from the very beginning adorned their catacombs with paintings of Christ, of the saints, of scenes from the Bible and allegorical groups, and Christian statues have been discovered that date to the first century. According to the Catholic Encyclopedia, "The idea that the Church of the first centuries was in any way prejudiced against pictures and statues is the most impossible fiction." However, it is important to distinguish between the use of images and the reverence paid to them.
With regard to the level of veneration, if any, paid to images in the early church, written sources are almost nonexistent. However, some conclusions can be made on the basis of what we do know. The early Christians' "monotheism, their insistence on the fact that they serve only one almighty unseen God, their horror of the idolatry of their neighbors, the torture and death that their martyrs suffered rather than lay a grain of incense before the statue of the emperor's numen are enough to convince us that they were not setting up rows of idols of their own. On the other hand, the place of honor they give to their symbols and pictures, the care with which they decorate them argue that they treated representations of their most sacred beliefs with at least decent reverence." 
Use of Icons
It seems that the tradition of showing respect and veneration to images developed gradually and as a natural consequence of cultural norms. "It would be natural that people who bowed to, kissed, incensed the imperial eagles and images of Caesar (with no suspicion of anything like idolatry), who paid elaborate reverence to an empty throne as his symbol, should give the same signs to the cross, the images of Christ, and the altar.
To the Byzantine Christian of the fifth and sixth centuries prostrations, kisses, incense were the natural ways of showing honor to anyone; … he was accustomed to treat symbols in the same way, giving them relative honor that was obviously meant really for their prototypes. And so he carried his normal habits with him into church." 
Such veneration spread in some measure to Rome and the West, but their home was the court at Constantinople, and to this day the descendents of the subjects of the Eastern emperor place a much higher importance on the veneration of icons than their western (Catholic) counterparts.
By the eighth century, icons had become a major part of eastern devotion. The walls of churches were covered inside from floor to roof with icons, scenes from the Bible, allegorical groups. Icons were taken on journeys as a protection, they marched at the head of armies, and presided at the races in the hippodrome; they hung in a place of honor in every room, over every shop; they covered cups, garments, furniture, rings; wherever a possible space was found, it was filled with a picture of Christ, Mary, or a saint.
Even more reverence was paid to icons believed to have miraculous origins, such as the image of Edessa, like the Shroud of Turin.
That veneration of these icons gradually became excessive is attested to by several sources, including a (perhaps slightly exaggerated) letter from the iconoclastic Emperor Michael II (r. 820-9):
They have removed the holy cross from the churches and replaced it by images before which they burn incense.... They sing psalms before these images, prostrate themselves before them, implore their help. Many dress up images in linen garments and choose them as godparents for their children.
The Iconoclastic Controversy
Although there was intermittent opposition to the veneration of images in the first seven centuries of the church, the issue first became a major point of controversy in the eighth century. The iconoclastic controversy began in earnest under Emperor Leo III (r. 716-41), a strong-willed man who opposed the veneration of images and began to persecute those who did so. Leo's iconoclastic position may have been influenced by Khalifa Omar II (717-20), who was unsuccessful in trying to convert the emperor to Islam but probably convinced him that pictures and images are idols, but he was also convinced of this by Christian opponents of icons who gained his ear.
In 726 AD, Leo III published an edict declaring images to be idols, forbidden by Exodus 20:4-5. He commanded that all such images in churches be destroyed, and the soldiers immediately began to carry out his orders throughout the empire. There was a famous picture of Christ, called Christos antiphonetes, over the gate of the palace at Constantinople, the destruction of which provoked a serious riot among the people.
Germanus, the patriarch of Constantinople, protested against the edict and appealed to the pope (729). But the emperor deposed him as a traitor (730) and had Anastasius (730-54), a willing instrument of the government, appointed in his place. The most steadfast opponents of the Iconoclasts throughout this story were the monks. It is true that there were some who took the side of the emperor but as a body, eastern monasticism was steadfastly loyal to the old custom of the Church. Leo therefore joined with his iconoclasm a fierce persecution of monasteries and eventually tried to suppress monasticism altogether.
Pope Gregory II (r. 713-31) responded to the appeal of the deposed patriarch with a long defense of images. He explains the difference between them and idols, with some surprise that Leo does not already understand the distinction. But Leo remained steadfast and the persecution continued to rage in the East. Monasteries were destroyed and monks were put to death, tortured, or banished. The Iconoclasts began to apply their principle to relics also, to break open shrines and burn the bodies of saints buried in churches.
At the same time, St. John of Damascus (d. 754), safe from the emperor's anger under the rule of the Khalifa was writing at the monastery of St. Saba his famous apologies "against those who destroy the holy icons." In the West, at Rome, Ravenna, and Naples, the people rose against the emperor's law.
In 731, Pope Gregory II was succeeded by Gregory III, who in that same year held a synod of 93 bishops at St. Peter's. All persons who broke, defiled, or took images of Christ, of His Mother, the Apostles or other saints were declared excommunicate. Leo then sent a fleet to Italy to punish the pope but it was wrecked and dispersed by a storm. Meanwhile every kind of calamity afflicted the empire; earthquakes, pestilence, and famine devastated the provinces while the Muslims continued their victorious career and conquered further territory.
Leo III died in June, 741, in the midst of these troubles, without having changed policy. His work was carried on by his son Constantine V (Copronymus, 741-775), who became an even greater persecutor of image-worshippers than had been his father. In 754 Constantine, taking up his father's original idea summoned a great synod at Constantinople that was to count as the Seventh General Council. About 340 bishops attended, although the most important sees refused to sent representatives to the puppet council. The bishops at the synod servilely agreed to all Constantine's demands. They decreed that images of Christ are either Monophysite or Nestorian, for -- since it is impossible to represent His Divinity -- they either confound or divorce His two natures. A special curse was pronounced against three chief defenders of images -- Germanus, the former Patriarch of Constantinople, John of Damascus, and a monk, George of Cyprus.
The Emperor Constantine V died in 775. His son Leo IV (775-80), although he did not repeal the Iconoclast law was much milder in enforcing them. He allowed the exiled monks to come back, tolerated at least the intercession of saints and tried to reconcile all parties. When Leo IV died, the Empress Irene was regent for her son Constantine VI (780-97), who was nine years old when his father died. She immediately set about undoing the work of the Iconoclast emperors. Pictures and relics were restored to the churches; monasteries were reopened.
Finally, the Patriarch of Constantinople and the Empress Irene sent an embassy to Pope Adrian I (772-95) acknowledging his primacy and begging him to come himself, or at least to send legates to a council that should undo the work of the Iconoclast synod of 754. The petition was granted, and about 300 bishops attended a council in Nicea, the site of the first ecumenical council, from 24 September to 23 October, 787.
The Second Council of Nicea confirmed the use of icons, condemned the Iconoclast leaders, and in opposition to the formula of the Iconoclast synod, declared of Germanus, John Damascene and George of Cyprus: "The Trinity has made these three glorious."
Twenty-seven years after this council, iconoclasm broke out again. The icons were again restored in 842, after which the iconoclastic movement gradually died out in the east. Icons continue to be a major part of Orthodox worship and devotion to this day. The Catholic Church continues to venerate images as well, though such images are not as central in the West as they are in the East. The Protestant Reformers generally opposed the use of icons, and icons continue to be generally avoided by most Protestants today.
Form of Orthodox Icons
Orthodox icons are typically egg tempura paintings on wood, often small. There is a rich history and rich patterns of religious symbolism associated with icons. Generally, icons used in Orthodox churches strictly followed formulas hallowed by usage originating in Constantinople.
The personal and improvisatory traditions of iconographic novelty familiar from Western religious art are largely lacking in the East. The Orthodox sometimes call them "windows into heaven." In the churches of those Eastern denominations, the nave is typically separated from the sanctuary by an iconostasis a wall of icons. Many religious homes in Russia, for example, have icons hanging on the wall.
Icons are often illuminated with a candle or jar of oil with a wick. (Beeswax for candles and olive oil for oil lamps are preferred because they burn very cleanly.) Besides the practical purpose of making them visible in an otherwise dark church in the days before electricity, this symbolically indicates that the saint(s) depicted are illuminated by the Christ, the Light of the World.
Veneration of Icons in Orthodox Christianity
Especially since the Iconoclastic Controversy of the 8th century, icons have played an essential part in public worship and private devotion in eastern Christianity. Icons are honored with traditional expressions of veneration in the East, including kisses, prostrations, offerings and incense. "As it is believed that through them the saints exercise their beneficent powers, they preside at all important events of human life and are hedl to be effective remedies against illness, to drive away devils, to procure both spiritual and temporal blessings, and generally to be powerful channels of divine grace." 
When Orthodox Christians venerate or show honor and respect for icons, they understand that they are merely expressing those feelings for the people and events depicted, and not for the icons themselves. To make this clear to the laity, worship of icons was forbidden by the same council that defended their veneration, the Second Council of Nicea. By venerating icons, Orthodox Christians acknowledge that matter is not inherently evil, but can be used by God. As the great icon-defender St. John of Damascus explained:
I do not worship matter; I worship the Creator of matter who became matter for my sake, who willed to take His abode in matter; who worked out my salvation through matter. Never will I cease honoring the matter which wrought my salvation! I honor it, but not as God. … Do not despise matter, for it is not despicable. God has made nothing despicable. (On the Divine Images 1:16-17) ### Important Specific Icons
Our Lady of Vladimir (right) is one of the most venerated Orthodox icons. Regarded as the holy protectress of Russia, the icon is displayed in the Tretyakov Gallery, Moscow.
Patriarch Luke Chrysoberges of Constantinople sent the newly-painted icon as a gift to Grand Duke Yury Dolgoruky of Kiev about 1131. The beautiful image was coveted by Yury's son Andrei the Pious who brought it to his favourite city Vladimir in 1155. When the horses that transported the icon stopped near Vladimir and refused to go further, this was interpreted as a sign that the Blessed Virgin wants to stay in Vladimir. To house the icon, the great Assumption cathedral was built there, followed by other churches dedicated to the Virgin throughout northwestern Russia.
In 1395, during Tamerlane's invasion, the image was taken from Vladimir to the new capital, Moscow. The spot where people and the ruling prince met the icon is commemorated with the Sretensky monastery. Vasili I of Moscow spent a night crying over the icon, and Tamerlane's armies retreated the same day. The Muscovites refused to return it back to Vladimir and placed it in the Assumption cathedral of the Moscow Kremlin. The image was also credited with saving Moscow from Tatar hordes in 1451 and 1480.
One of the most exquisite icons ever painted, Our Lady of Vladimir is imbued with universal feelings of motherly love and anxiety for her child. By the 16th century the Vladimirskaya (as the Russians call it) was a thing of legend. It was even rumoured that the icon was painted by St Luke on the Lord's table of the Last Supper. The venerated image was used in coronations of tsars, elections of patriarchs, and other important ceremonies of state.
But its most important service was yet to come. In December 1941, as the Germans approached Moscow, Stalin order that the icon be taken from a museum and placed in an airplane and that it be carried around the besieged capital. Several days later the German army started to retreat.
Another important icon in Russian Orthodoxy is Our Lady of Smolensk. With the population of 200,000 inhabitants, Smolensk was probably the largest city in the 15th-century Lithuania. Three Smolensk regiments proved decisive during the Battle of Grunwald against the Teutonic knights. It was a severe blow when the city was recaptured by Vasili III of Russia in 1514. To commemorate this event, the tsar founded the Novodevichi convent in Moscow and dedicated it to the holy icon of Our Lady of Smolensk.
The Black Madonna of Częstochowa (Czarna Madonna or Matka Boska Częstochowska in Polish) is a 14th century icon of a Black Madonna. It is credited with miraculously saving the monastery of Jasna Góra from a Swedish onslaught.
- "Veneration of Images." The Catholic Encyclopedia.
- "icon." Oxford Dictionary of the Christian Church, 3rd ed. (Oxford UP, 1997), p. 815.
- "Iconoclasm." The Catholic Encyclopedia. This article incorporates some public domain text from this source.
- "Icons." Wikipedia, the free encyclopedia. This article incorporates some public domain text from this source.