 Byzantine architecture of the time favored the incorporation of spolia to celebrate the triumph of Christianity over Paganism, as much of the spolia was sourced from Greek and Roman temples throughout the Empire.Dating of the Omphalos has varied, with some dating it to the reign of Justinian, and some dating it as a later addition, particularly to the reign of Basil I (867-886).The evidence used to argue for this later dating is the seemingly odd placement within Hagia Sophia.