Paulus describes a part on the south side as being inclosed for the emperor, and in Porphyrogenitus we read that the emperor had his seat “near the Holy Doors on the right-hand side.” It is probable that opposite the emperor’s throne there was another bishop’s chair, for that in the bema might only be occupied by the bishop in his own diocese. Grelot indeed reports that the emperor’s and bishop’s thrones were opposite one another. _Nave._--We now come to the central division of the church, the naos or nave, the square space beneath the dome contained between the four main piers: its centre was called _omphalos_, _mesomphalos_, or _mesonaos_. The pavement, according to the poet Paul, was covered with white Proconnesian marble and darker Bosporus stone. In the opening lines of the description before given he seems to compare the veined marble to flowing streams, or foam-flecked sea, and the ambo is likened to an island rising from the sea. According to Glycas and Codinus the first pavement was of various hues like the ocean. The Anonymous, in comparing a pavement which he says was laid down afterwards with this supposed earlier one, says that “messengers were sent to Proconnesus, and marble of a green colour was worked there, as is seen now like rivers flowing into the sea.” Codinus says, “four rivers of leek-green marble were like the four streams which flow from Paradise to the sea.” _As is seen now_ certainly seems to bring something definite before our eyes, and so far as the pavement can be seen through the narrow chinks of the matting there is much to confirm this part of the Anonymous. Grelot tells us that the pavement is laid in compartments. It is of whitish gray Proconnesian marble, laid in slabs about 4 × 10 feet, with here and there strips of verde antique about 2 feet wide, which suggest the quartering of the floor by a great cross. Moreover the square of rich Alexandrine work still existing, and figured by Salzenberg, lies on a diagonal, and would thus exactly occupy one of four square spaces left in the angles (see Fig. 5). Now in the palace the floor of the bedchamber of Basil had four rivers or streams of Thessalian-green marble which seemed to flow away from the centre, and the quarters were filled with mosaics of large eagles.[140] It may also be noticed that four rivers are depicted as flowing away from the cross on the central bronze door of narthex. Many parallel examples of pavements, still existing, confirm the Anonymous in this respect. The mosaic floors of Italy furnish many instances where the four rivers of Eden are represented in the several angles as human forms pouring from urns, waters which are inscribed with the names Gihon, Tigris, Euphrates, and Pison. The design of the pavement of the Baptistery at Florence has been much disturbed, but it seems to have represented flowing streams, which led from the font in the middle to the doors like four paths. It