 The dome , octagonal in shape , stands prominently on top of the centre of the cella . It was supported by four now @-@ destroyed columns which were located directly beneath it . The integrated bell tower has been built on top of the narthex , as was customary in contemporary Byzantine church architecture , and extends from the rectangular main structure . The bell tower was originally rectangular , though it is now partially ruined . It was reached from the south by means of a stone staircase . 
 The dome , octagonal in shape , <a href='uninflect' title='1'><mark>stands</mark></a> prominently on top of the centre of the cella . It was supported by four now @-@ destroyed columns which <a href='uninflect' title='2'><mark>were</mark></a> located directly beneath it . The integrated bell tower <a href='been_done' title='3'><mark>has</mark></a> been built on top of the narthex , as was customary in contemporary Byzantine church architecture , and <a href='uninflect' title='4'><mark>extends</mark></a> from the rectangular main structure . The bell tower was originally rectangular , though it is now partially ruined . It was reached from the south by means of a stone staircase . 
The dome , octagonal in shape , stand prominently on top of the centre of da cella . It was supported by four now @-@ destroyed columns which was located directly beneath it . The integrated bell tower done been built on top of tdanarthex , as was customary in contemporary Byzantine church architecture , and extend from the rectangular main structure . Thdaell tower was originally rectangular , though it is now partially ruined . It was reached from thedauth by means of a stone staircase .