It is quite certain from Procopius and the poem of the Silentiary that the vaults of Justinian’s church were covered with mosaic. They both describe the brilliance of the gold glittering surface, but do not mention any figures. In such detailed descriptions this silence goes far to show that there was originally no storied scheme of imagery, like that which the Poet so fully traced out on the curtains and iconostasis. It seems equally certain that where, describing the dome on the strong arches, overhanging the interior like the firmament which rests on air, he says, “at the highest point was depicted (epigraphe) the cross, Protector of the City,” we are to understand that a great cross in mosaic expanded its arms on the zenith of the dome, and that the background was strewn with stars. Now this is a well-known scheme, and it is found at an earlier date in the chapel of Galla Placidia at Ravenna, and later it is mentioned by Porphyrogenitus in a description of a domed apartment in the palace. The stars on the dome are more than once referred to in the poem (page [36]), and it is probable that the surfaces between the ribs as well as the central circle had gold stars set in azure, the ribs being of gold; nothing less would seem to justify “the firmament of the roof its rounded expanse sprinkled with the stars of heaven.”
It is evident that, however easily figures and pictures might be added here and there at various dates, the church, being once incrusted with mosaic, would at no subsequent time have had the enormous areas of tesserae removed to be again renewed.
It follows that the ground, and any patterns evenly distributed in every part of the vaults, are assuredly of the first work. First among such designs is a jewelled cross thirteen feet high, which is blazoned on both ground floor and gallery vaults, and which must have been repeated some twelve times twelve. We give an outline of one of the smallest vault compartments in the church, the irregular space to the east directly south of the bema: here three of the crosses can still be seen through Fossati’s colouring, their interlocking arms spreading over the whole field. This form of cross, with lobed ends, is found set in a circle of stars, in the mosaic apsoid of S. Apollinaris in Classe. ([Fig. 70].)
A similar argument applies to other forms which occur with equal frequency. A square panel of ornament which alternates with the crosses, certain diapers, the bands up the edges of the aisle vaults, and the small circles each containing the six-armed cross or monogram at the centre of these compartments, would all seem to be parts of the original work, and these simple elements we believe formed the first scheme of decoration. Texier figures a mosaic from Salonica made up of crosses. The splendid simplicity of such a scheme seems entirely in harmony with S. Sophia, for even figures would disturb the beauty of the expanse which at each movement glitters like a web of golden mail swayed by a breeze.
Later Mosaics.—For the mosaics displaying figures we refer back to Salzenberg’s description. Much further information might have been gathered if he had given copies of the inscriptions which exist, in however incomplete a state. His section (Plate x.) shows that a long inscription surrounded the arch of the apse, but in his text he only gives the last few letters ϹΕΙΕ ΠΑΛΙΝ; this possibly belonged to the words ἀνεστήσειε πάλιν, “Set up again,” and the whole may have contained the name of the emperor under whom this restoration was effected. (See below, p. [287].)
On the great lunette of the wall of the south side also, where the tiers of saints and prophets seem a part of a scheme representing the Church triumphant, or a Benedicite, two monograms occur (see Salzenberg’s Plate ix.); only the first, which reads ΚΥΡΙΕ, is figured in the text; it is evidently a part of the well-known invocation, ‘Lord, help,’ which requires the name of an emperor or artist to complete it.
An inscription between these monograms is partly given in the text; and supposing it to be correctly rendered the whole probably read “Lord, help” (name who painted this wall) “of the Immortal Wisdom” (with the figures) “of the saints”.
The entire later scheme of the mosaics must have corresponded closely to that in the New Church in the palace built by Basil, which is described by Porphyrogenitus. Here, at the centre of the dome, was the human form of Christ embracing the whole world in His regard; below were ranges of angels. In the apse was the figure of the Virgin with arms uplifted in prayer, “a choir of apostles, martyrs, prophets and patriarchs filled the other spaces of the whole church.” This in turn resembles very closely the iconography at S. Luke’s.
Fig. 71.—Restoration of Throne at Crown of Pentecost Dome.