<P> Earthquakes in August 553 and on 14 December 557 caused cracks in the main dome and eastern half - dome . The main dome collapsed completely during a subsequent earthquake on 7 May 558, destroying the ambon, altar, and ciborium . The collapse was due mainly to the unfeasibly high bearing load and to the enormous shear load of the dome, which was too flat . These caused the deformation of the piers which sustained the dome . The emperor ordered an immediate restoration . He entrusted it to Isidorus the Younger, nephew of Isidore of Miletus, who used lighter materials and elevated the dome by "30 feet" (about 6.25 meters or 20.5 feet)--giving the building its current interior height of 55.6 meters (182 ft). Moreover, Isidorus changed the dome type, erecting a ribbed dome with pendentives, whose diameter lay between 32.7 and 33.5 m . Under Justinian's orders, eight Corinthian columns were disassembled from Baalbek, Lebanon, and shipped to Constantinople around 560 . This reconstruction, giving the church its present 6th - century form, was completed in 562 . The Byzantine poet Paul the Silentiary composed a long epic poem (still extant), known as Ekphrasis, for the rededication of the basilica presided over by Patriarch Eutychius on 23 December 562 . </P> <P> In 726, the emperor Leo the Isaurian issued a series of edicts against the veneration of images, ordering the army to destroy all icons--ushering in the period of Byzantine iconoclasm . At that time, all religious pictures and statues were removed from the Hagia Sophia . After a brief reprieve under Empress Irene (797--802), the iconoclasts made a comeback . The Emperor Theophilus (829--842) had two - winged bronze doors with his monograms installed at the southern entrance of the church . </P> <P> The basilica suffered damage, first in a great fire in 859, and again in an earthquake on 8 January 869, that made one of the half - domes collapse . Emperor Basil I ordered the church repaired . </P> <P> After the great earthquake of 25 October 989, which collapsed the Western dome arch, Emperor Basil II asked for the Armenian architect Trdat, creator of the cathedrals of Ani and Argina, to direct the repairs . He erected again and reinforced the fallen dome arch, and rebuilt the west side of the dome with 15 dome ribs . The extent of the damage required six years of repair and reconstruction; the church was re-opened on 13 May 994 . At the end of the reconstruction, the church's decorations were renovated, including the addition of four immense paintings of cherubs; a new depiction of Christ on the dome; a burial cloth of Christ shown on Fridays, and on the apse a new depiction of the Virgin Mary holding Jesus, between the apostles Peter and Paul . On the great side arches were painted the prophets and the teachers of the church . </P>

The byzantine church of hagia sophia was influential in the history of architecture because it