How does Early Christian and Byzantine portraiture represent both a continuation of and a break from the past?

   Early Christian and Byzantine portraiture is the same because the styles look the same as when they were used in the past.  Egyptians inherited the styles of the Romans, and used them, but they were willing to change them to their advantage, as we can clearly see in a portrait of a boy inscribed in Greek. (http://www.metmuseum.org/special/se_event.asp?OccurrenceId={83B5C9F5-AD4E-11D3-936B-00902786BF44}) The Roman-conquered Egypt sometimes used paintings like these to place over the heads of their mummies instead of the previously used styles. So, Egyptians used the same mummifications process, but they changed the portraits and the language in which the name was inscribed on the mummy. The Egyptians changed the way that the portraits looked, but were not willing to change everything i.e. the entire process and art of the Egyptian mummified pharaohs.