Till the fourth century portraits of Christ were rare. The earliest iconographic representations seem to have been of the apostles, especially of Peter and Paul, though Christ was shown in scenes from the Gospels.  Towards the end of the third century there appeared a kind of collective     portrait of Christ seated among the apostles, an image based on a common classical form depicting the teacher and his disciples, or a group of learned men gathered round their leader.
There is little doubt that Christians followed contemporary practice in having funerary portraits painted of distinguished church members. These portraits showed the bust of the person, facing forward, often enclosed within a medallion. There may have been some reserve on the part of the church leaders towards these images in the early centuries, for fear of idolatry. But when the pagan ancestor cult was  declared illegal at the beginning of the fifth century such portraits of saints survived to become portable icons