The Hagia Sophia was completed in just 5 years and "Earthquakes in August 553 and on 14 December 557 caused cracks in the main dome and eastern half-dome. The m

The Hagia Sophia was completed in just 5 years and "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,[21] 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.[18] These caused the deformation of the piers which sustained the dome.[18] 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"[18] (about 6.25 meters or 20.5 feet)[clarification needed] – giving the building its current interior height of 55.6 meters (182 ft).[22] Moreover, Isidorus changed the dome type, erecting a ribbed dome with pendentives, whose diameter lay between 32.7 and 33.5 m.[18] Under Justinian's orders, eight Corinthian columns were disassembled from Baalbek, Lebanon, and shipped to Constantinople around 560.[23] This reconstruction, giving the church its present 6th-century form, was completed in 562."