Patriarch Kirill of Moscow
Days before the final decision on the conversion was made, Ecumenical Patriarch Bartholomew I of Constantinople stated in a sermon that "the conversion of Hagia Sophia into a mosque would disappoint millions of Christians around the world”, he also said that Hagia Sophia, which was "a vital center where East is embraced with the West", would "fracture these two worlds" in the event of conversion. The proposed conversion was decried by other Orthodox Christian leaders, the Russian Orthodox Church's Patriarch Kirill of Moscow stating that "a threat to Hagia Sophia [wa]s a threat to all of Christian civilization".