The ambulatory type appears to be early, and the examples in Constantinople seem to date from the sixth to the ninth century. It may therefore be concluded that, unless there is proof to the contrary, the south church is the earlier. In that case the southernmost parts of the two large piers which separate the two churches represent the old outer wall of the original south church, whose eastern chapels were then symmetrical. To this the north church was added, but at some subsequent date the apses of the south church demanded repair and when they were rebuilt, the north-eastern chapel was enlarged by the cutting away of the old outer wall. To this period also belongs the present inner narthex. The fact that the head of the terminal niche at the south end of the north narthex remains above the communicating door shows that the south narthex is later. The outer narthex and south gallery are a still later addition.
Fig. 43.
Fig. 44.