The impost capital is probably first seen in the great cistern, also of Justinian's day. I may here repeat what I have said elsewhere.[7]
"Strygowski[8] regards this impost-capital as the work of the builder of the great cistern, who he thinks may have been Anthemius, here proving his fitness for the great work of S. Sophia. It was, he shows, an architectural revolution. The capital, with undercut volutes, was suitable for a straight architrave, but not for the arch. Hence a piece was inserted to transfer the weight from the angles to the centre. The Theodosian age used an inserted impost. The constructive activity of the age of Justinian produced the impost-capital.
As to design, the capitals lying neglected about the city, together with those _in situ_ in the churches and cisterns, furnish a perfect museum of the types with which others, dispersed over the whole area of the empire, agree in the minutest particulars of design and workmanship. The acanthus leaves, so familiar through all the work of the centuries--from the Golden Gate (388) onward, and the portico to S. John of the Studium a century later--assume the beautiful "windblown" design in the ruins near the "Rose Mosque."[9]
The second feature is the arrangement which unites the longitudinal with the central building and makes the whole effect of the interior of one piece by relating every piece of work, pillar, arch, semi-dome, to the one vast central dome which crowns the whole. From without, but more clearly from within, the architecture of S. Sophia is seen to form one entire and perfect whole. It is impossible to conceive it deprived of a single feature without the sacrifice of the whole. To mutilate would be to destroy.
Seen then in its grandeur at S. Sophia the work of Justinian changed the appearance of the whole city. Procopius in his _Aedifices_ records what was when he wrote in 558, a complete list of what had been built in the reign. Everywhere there were arising, as though by an enchanter's wand, palaces, churches, baths, aqueducts, great cisterns supported on exquisitely carved columns, new markets, houses for the great nobles, barracks, hospitals, convents. The splendour and beauty of the new city, its richness of decoration, marbles, statuary, mosaics, struck all beholders with amaze. The chroniclers, who in other times would have been satisfied to tell of military successes and court intrigues, now tell of measurements and designs, and collect lists of gems and splendours of decoration. The reign of Justinian, in spite of many foreign dangers, and oppression at home, is the most magnificent period of early Byzantine history; and the magnificence seemed to be expressed in the buildings of Constantinople.