_North and South Porches._--Much of the confusion at the north-west and south-west angles is the result of Turkish attachments, including the western minarets, which were built in the last quarter of the sixteenth century. The plan of gynaeceum floor furnishes the best key to the former arrangement, for where there is Byzantine work above, it must once have existed below. Comparing the first floor and roof plans in Salzenberg with the ground plan, it becomes apparent that the main block was originally finished both at north-west and south-west angles to the general square of building. The two staircases now at these angles were added as extra buttressing masses; the original stairs being the four in the piers of north and south sides. The north and south porches, with extra building above the latter on the first floor, were also additions. Besides the irregularity and inferior style of these buildings the following evidence should be noticed. The actual form of the north-west angle on the gallery floor; and the natural reading of the three plans when laid one over the other; broad arches, which pass across the porches; the fact that the arch in south porch (dotted in C on Figure 24, see also Fossati, Plate i.) now has no office; and that above the door at this end of narthex, there is a window which now merely opens into the south porch. An examination of the exterior on the south side shows that the south-west staircase was built before the porch, or the part above it at least, because a straight joint in the walling, and the form of the roofing, here clearly make evident that the apex of the gable roof was originally over the centre of the staircase, and that the slope has been subsequently run forward to cover the part above the porch. In considering all the other irregularly attached buildings, together with the historical evidence, it seems clear that the church as designed and first built was externally a regular parallelogram, interrupted only by the projection of the apse at the east end; which was itself masked by a range of low chambers against the east wall, through which there were two entrances to the church as at present, and to which other two doors, in the east wall, still visible but now blocked, gave access. The other external doors, besides those from narthex, being two on the north and one in the south wall; together with two external doors at the gynaeceum level, one of which probably gave access to the gallery along which the emperor passed to the church, and the other, to the north, may have led to the cells of the clergy.