Nor is this strange. A masterpiece cannot be reproduced. But we must seek farther for a complete explanation of the fact. While S. Sophia is, from one point of view, a culmination, it is, from another point of view, a stage in a process of development. The combination of basilican and domical features which it displays is a tribute at once to the influence of old tastes and to the influence of a new fashion. The result of the cross, so to speak, of the two influences was superb, and might well have arrested further change. But considerations, practical and theoretical, were at work urging movement onwards. Although the dome of S. Sophia was a great triumph, it was not a complete success. It rested squat upon the building, when viewed from without. And what was more serious, its thrust against the walls of the church was so strong as to demand external buttressing to prevent a fall. Furthermore, while to stand in a forest of pillars was impressive, it was a pleasure that interfered with the duty of following readily the services at the altar, and broke the unity of the congregation of worshippers. Then, men had grown somewhat weary of the basilica, and were enamoured with the dome. Accordingly, a logical necessity urged the mind to draw all the conclusions involved in the premises which had won the faith of the world of Art. Henceforth, the architectural ideal would be a domed rectangular edifice as free from pier or pillar, and as wide open to view, if that were possible, as the area beneath the dome of the Pantheon. Consequently, the columns or piers bordering the nave decrease in number until they are reduced to the four necessary to carry the arches upon which the dome rests. Lateral aisles become narrow; galleries disappear, or are represented by a gallery only over the narthex. Indeed, in such churches as S. Saviour-in-the-Chora, the piers that bear the dome are not free-standing supports, but narrow projections from the walls of the edifice; so that the interior is practically open to view in all its length and breadth, having neither aisles nor gallery. In dealing with the dome, the thrust was reduced, by carrying a cylindrical or polygonal turret (drum) to a moderate height above the roof, and surmounting the structure with a cupola. That the fundamental idea inspiring this movement, from the basilica to the perfect development of a domical building, was legitimate, and capable of producing magnificent results, cannot be disputed. But, for some reason, Byzantine architects in Constantinople did not realise their ideal to the extent we might expect. At least, no large church constructed on this plan is found in the city. Then a dome set upon a turret lacks mass and dignity, when viewed from without, and fails to dominate the interior, or lift eye and heart upwards, the moment the worshipper crosses the threshold. To look into such a dome and admire its mosaics is also difficult; sometimes, even painful.