Pope Francis and UNESCO are concerned by Turkey’s decision to restore Hagia Sophia’s status as a mosque after it had served for 76 years as a landmark museum that bore testament to Istanbul’s dual Christian and Islamic history.“My thoughts go to Istanbul. I think of Santa Sophia. and I am very pained,” Pope Francis said during his weekly blessing Sunday in St. Peter’s Square. The United Nations Educational, Scientific and Cultural Organization (UNESCO) warned over the weekend that Turkey’s decision could impact the site’s status as a World Heritage Site.The ancient structure was first built as a Byzantine church around 537 AD. It was converted to a mosque in 1453. The Ottomans built minarets alongside the vast domed structure, while inside they added panels bearing the Arabic names of God, the Prophet Mohammad and Muslim caliphs.In an attempt to recognize the structure’s dual heritage and to make a statement about Turkey’s secular nature, former Turkish president Mustafa Kemal Ataturk turned it into a museum in 1934. The golden mosaics and Christian icons, obscured by the Ottomans, were uncovered again when Hagia Sophia became a museum.The site was inscribed onto UNESCO’s World Heritage List in 1985 under Historic Areas of Istanbul, along with other points of significance in the city.“Hagia Sophia is an architectural masterpiece and a unique testimony to interactions between Europe and Asia over the centuries. Its status as a museum reflects the universal nature of its heritage, and makes it a powerful symbol for dialogue,” UNESCO Director-General Audrey Azoulay said over the weekend as she issued a rare political statement.She spoke with Turkey’s ambassador to UNESCO about the matter on Friday night. Several letters on the matter have also been exchanged between UNESCO and Turkey.UNESCO said it had not been informed about Ankara’s decision to close the museum and reopen the site as a mosque.“It is regrettable that the Turkish decision was made without any form of dialogue or prior notice,” UNESCO said.UNESCO called upon Turkey to “initiate dialogue without delay in order to prevent any detrimental effect on the universal value of this exceptional heritage, the state of conservation of which will be examined by the World Heritage Committee at its next session.”That committee has been scheduled to meet at the end of June and the start of July. In light of the COVID-19 pandemic, that meeting has been delayed and no new date has been set.According to the World Heritage List, Hagia Sophia is a “model for an entire family of churches and later mosques, and the mosaics of the palaces and churches of Constantinople influenced both Eastern and Western art.”Turkish President Recep Tayyip Erdogan has been unfazed by the international uproar over his decision. He made the move after a top court ruled the ancient building’s conversion to a museum was illegal. Erdogan has sought to shift Islam into the mainstream of Turkish politics over his 17 years at the helm.By reversing one of Ataturk’s most symbolic steps, which underlined the former leader’s commitment to a secular republic, Erdogan has capped his own project to restore Islam in public life, said Soner Cagaptay, director of the Turkish Research Program at the Washington Institute for Near East Policy.“Hagia Sophia is the crowning moment of Erdogan’s religious revolution, which has been unfolding in Turkey for over a decade,” he said, pointing to greater emphasis on religion in education and across government.Erdogan plans to open the site to Muslim worshipers within two weeks, but he has promised that visitors to Turkey can still visit the site as they would other mosques.Reuters contributed to this report.