216 BYZANTINE CHURCHES CHAP, xiv to the southern wall are roundels with radiating voussolrs in stone and brick5 and if one may judge from the fact that the string-course does not fit the face of the wall, parts of the exterior of the church were incrusted with marble. The round-headed windows of the dome cut into its cornice. Under the church is a cistern1 which Bondelmontius deemed worthy of mention.2 Until some twenty years ago extensive substructures were visible on the north-east of the churchj affording homes for poor Greek families.3 They were probably the foundations of the lofty monastery buildings whose windows commanded the magnificent view of the Golden Horn that doubtless suggested the epithet Pantepoptes3 under which the Saviour was worshipped in this sanctuary, S. Saviour Pantepoptes is the most carefully built of the later churches of Constantinople. The little irregularities of setting out so common in the other churches of the city are here almost entirely absent This accuracy of building, the carving of the string-courses, and the remains of marble decoration both within and on the exterior,, prove exceptional care* For details see Figs, 683 y25 75. 1 Die byzantmmhen WamrbehtilUr <von K.P.^ von Dr. P. Forcheimer und Dr. J. Strzygowski, pp. 106-7. 2 Libritm insularum Archipelago 65, 3 Paspates, p. 314.