After Constantinople's Roman cathedral collapsed during a revolt opposing the colored charioteer parties, Byzantine emperor Justinian ordered a grand new one for his capital, to be built in a record time of five years by two leading engineers, not proper architects, one of which died on the job and was succeeded by a nephew. The giant job included selecting and gathering enormous amounts of materials, such as a Rhodes alternative for Rome's volcanic wonder-concrete. Miscalculations in the design of the giant central cupola and its pressure-devolution systems, aggravated by seismic activity, nearly lead to collapse. The lavish decoration in the finest marble, mosaics and so on also shows signs of haste and later elaborations by emperors until the Ottoman conquerors turned it into a mosque, with a true Blue Mosque counterpart, and ultimately a museum in modern Turkey.
