information:extraction, structural:expansion, stylistic:tone, linguistic:voice_change
Theodosius to Justinian

After adoption of Christianity as the only permissible Roman state religion under Theodosius I, Christian art began to change not only in quality and sophistication, but also in nature. This was in no small part due to Christians being free for the first time to express their faith openly without persecution from the state, in addition to the faith spreading to the non-poor segments of society. Paintings of martyrs and their feats began to appear, and early writers commented on their lifelike effect, one of the elements a few Christian writers criticized in pagan art—the ability to imitate life. The writers mostly criticized pagan works of art for pointing to false gods, thus encouraging idolatry. Statues in the round were avoided as being too close to the principal artistic focus of pagan cult practices, as they have continued to be (with some small-scale exceptions) throughout the history of Eastern Christianity.

Nilus of Sinai (d. c. 430), in his Letter to Heliodorus Silentiarius, records a miracle in which Saint Plato of Ankyra appeared to a Christian in a dream. The saint was recognized because the young man had often seen his portrait. This recognition of a religious apparition from likeness to an image was also a characteristic of pagan pious accounts of appearances of gods to humans, and was a regular topos in hagiography. One critical recipient of a vision from Saint Demetrius of Thessaloniki apparently specified that the saint resembled the "more ancient" images of him—presumably the 7th-century mosaics still in Hagios Demetrios. Another, an African bishop, had been rescued from Arab slavery by a young soldier called Demetrios, who told him to go to his house in Thessaloniki. Having discovered that most young soldiers in the city seemed to be called Demetrios, he gave up and went to the largest church in the city, to find his rescuer on the wall.

During this period the church began to discourage all non-religious human images—the Emperor and donor figures counting as religious. This became largely effective, so that most of the population would only ever see religious images and those of the ruling class. The word icon referred to any and all images, not just religious ones, but there was barely a need for a separate word for these.