Answer: D - The artworks depict Byzantine Emperor Justinian I and his wife, Empress Theodora. Both mosaics were installed in The Basilica of San Vitale in Ravenna, a city in present-day Italy. Byzantine mosaics consisted of small pieces of colored tile affixed to a wall (or possibly to another interior surface in a building) to create portraits or patterned images. The tiled depictions of Justinian and Theodora are two of the most notable examples of medieval mosaics, and they are similarly two of the most notable works of Byzantine art.