How did Byzantine sculpture become more abstract after the reign of Justinian I?

Following the reign of Justinian I, Byzantine sculpture shifted away from the naturalistic representation that had characterized the Classical world, moving instead toward a more abstract and stylized aesthetic.1

This transition was marked by several key developments:

• Stylization of Forms: Even when architectural elements like capitals incorporated animal or bird motifs, these were no longer rendered with naturalism. Instead, they were treated as components of a balanced, overall pattern.1
• Decline of Three-Dimensional Sculpture: Large-scale, three-dimensional representational sculpture, such as portrait statues of emperors, largely fell out of fashion after the time of Justinian I.1
• Shift to Low Relief: Figural compositions in high relief, which had previously adorned sarcophagi and church walls, were replaced by flat slabs featuring low-relief, often geometric, ornamentation.1
• Functional Evolution: These flat, decorative slabs were primarily used for architectural screens between the church body and the sanctuary, eventually evolving into the iconostases that became universal in Orthodox churches.1

This move toward abstraction reflected a broader artistic trend in the Byzantine Empire that prioritized symbolic, static images over the naturalistic narrative traditions of antiquity.23