I was curious about the distinction between icons and other artistic works so I have been reading the two volumes of The Theology of Icons by Leonid Ouspensky
The Old Testament prohibited the display of images for fear of idol worship (except for the Temple in one instance) since God was not visible. With the Incarnation--when God became Man--that is, when Jesus was born in the flesh--the Old Testament prohibition ceased to be meaningful. Church tradition held that an image of Christ was preserved on a cloth he used to wipe his face and Luke the Evangelist painted images of Mary.
The Orthodox church maintains to this day that the Image is equal to the Word. They believe this comes from the Traditions of the earliest churches founded by the Apostles. Raised as a Protestant that is difficult for me to grasp. For us the Word, in the form of the King James Bible or a modern variation, is the one and only source of Christian inspiration.
The Byzantine Empire (the historians' name for the Eastern Roman Empire that survived until 1453 long after Rome itself fell under the control of Goths around 476) experienced two waves of iconoclasm in the eighth and ninth centuries. As a result, the Orthodox Church emerged with a firmly articulated view on images. The Roman Catholics did not have to deal with this problem and encountered some difficulty because there was kickback by the theologians around Charlemagne over a badly translated text from the last Council to firmly endorse images.
The Orthodox took a more restrictive view of what was an appropriate image than the Catholics and that was one of the lesser issues that led to a split in Christianity between the Pope in Rome and the Patriarchs in the East in 1054. Roman Catholicism and Orthodoxy have never healed the division. The deviation in the depiction of images grew more evident as the Western church found Renaissance artistic styles acceptable, but the Orthodox church preserved traditional forms.
The Catholics didn't address the issue seriously until the Council of Trent (1545-63) after the iconoclastic Protestants had split the Western church and Catholics were launching the Counter Reformation.
In the mid-16th century the formulaic tradition began to break down in the Orthodox world as Western influences began to impact iconographers and the Patriarchs accepted and even defended some of the stylistic changes. Icons are still being produced today, some preserving a traditional style and others adopting more modern elements with perspective and more realistic, less abstract, human forms.
The classic icon formula is best represented by Andrei Rublev (c. 1360’s – c. 1430) who is perhaps the most honored iconographer in Russia today. He was a monk and part of the veneration of icons is bound up with the sacred spirit that animates their creation. The classic icon is associated with the hesychast movement that was very influential among the Orthodox, but had no significant influence on Roman Catholics.
This is the traditional image of Christ. "The Saviour not made with hands."
The Old Testament Trinity by Andrei Rublev
The classic icon cannot display what is not physical, so the Trinity (God, the Father, Son, and Holy Spirit) can only be depicted from this Old Testament event in Genesis 18:1-15. The depiction of the New Testament Trinity became a contentious issue in the 16th century.
Our Lady of Vladimir by Simon Ushakov, 1652
This is a classic pose: the Virgin Umilenie or the Virgin of Compassion/Tenderness. There are 3 such classic poses for the Virgin and Child.
These icons are found in the Tretyakov Gallery in Moscow.