The history of icons may be divided into three periods or stages. These give us an idea about the development of thought concerning Church iconography:
The period of symbols . Symbols were used on a large scale in the first two centuries, where Christ was represented as the Good Shepherd, a fish, or was hidden under the first of two Greek letters of His Name Khristos (Χριστός).
The phase of biblical icons. These were used by the early Church for the purpose of education.
The phase of eschatological icons. In the fourth century, Christianity became the official religion of the Roman Empire and peace spread throughout the Church. This led to the appearance of two contradictory attitudes: the palace of the Emperor opened its doors to some churchmen who then deviated from their original spiritual mission, while others were anxiously awaiting the last coming of the Lord (Parousia). Church worship and Church icons of this period bore a strong eschatological attitude, such as icons of martyrs and saints crowned with glory, icons of angels, and icons of prophetical visions.