The Imperial Palace of Constantinople is poorly known. After all, the Sultan Ahmet Mosque is built right on top of it and excavation is impossible. Still, we have at some information from the book On Ceremonies by the Byzantine emperor Constantine VII Porphyrogenitus (r.945-959). This remarkable treatise contains descriptions of the "Palatium Magnum", and parts have been investigated. Several splendid mosaics from the sixth century CE have come to light during excavations that took part in 1935-1938, 1951-1954, and 1983-1997. They have been left in situ, and can be seen in İstanbul's Mosaic Museum.
There's more to these mosaics than meets the eye. Below the surface is a layer of about thirty to fifty centimeters deep, made of packed quarry stone (the stratumen). This gave stability to the second stratum, a ten centimeter layer of mortar screed, which was covered by an insulating layer soil, charcoal, and lime. This stratum was, in turn, topped by stone chips, which was covered by a layer of mortar in which hundreds of thousands of splendidly colored little stones (tesserae) were embedded. The small cubes, made of glass, colored lime, or terracotta, were about 5 mm long, which means that there were about 40,000 tesserae per square meter; as the size of the mosaic is about 2,000 square meter, surrounding a large court, the grand total is a fantastic eighty million! Unfortunately, only some 250 square meters have been found - still sufficient for no less than 150 figures of humans, animals, and mythological creatures.
Although only one eighth of the surface of the mosaics has survived, we get a general idea of the themes. There were hunting scenes, representations of animals, playing children, and bucolic landscapes (including a rare picture of a watermill). The most striking elements are the fantastic animals: there's a griffin devouring a lizzard, and a little bit further, one can see a chimaera about to be attacked by the hero Bellerophon.
None of these figures could be identified as specifically Christian. The children on the dromedary may indeed be pagan: it may be a representation of the triumphal voyage of Dionysus (and Pan?) from India. Written texts were not found, nor are there boundaries to separate the various scenes, as can be seen on contemporary mosaics like those in Theodorias.
The combination of the various elements may strike us as odd: what are those playing children doing between the hunting scenes? The fact that there are no inscriptions, suggests that to most visitors in the sixth century, the meaning was self-evident, or could be discovered without too much study.
The artists were really capable men or women, who knew enough of the anatomy of human beings and animals to make perfect figures. The children playing hoop are not small adults, but have the proportions of children - it may be noted that this scene is a parody on the circus games. The deer are remarkably realistic. The artists' qualities are especially clear when we watch the mythological beings, which are entirely plausible. The griffin, for example, is based on a tigress, and yet it has become a credible creature.
Finally, a word about the date of the mosaics. As already indicated, the mosaic is laid on several layers that were necessary to stabilize this work of art. In those strata, pieces of pottery were found that can be dated to the sixth century. This makes it very likely that it was created for the emperor Justinian (r.527-565), who is known to have rebuilt the palace after the Nika riots, which had destroyed a substantial part of the Great Palace. However, other rulers, like Anastasius (r.491-518), Justin I (r.518-527), or Mauricius (r.582-602) cannot be excluded. And of course, laying eight million small stones will take a lot of work, so it is likely that the work was not finished in a brief period.