ROME – Amid a chorus of resistance from the global Orthodox world, Turkey’s State Court ruled Friday to revert Istanbul’s Hagia Sophia, one of the most iconic monuments for both Christianity and Islam, to a mosque.

Announced July 10, the decision annuls a 1934 decision to convert the building into a museum, ruling that the conversion was unlawful.

Built under Byzantine Emperor Justinian, the 1,500-year-old structure for centuries was the heart of the Eastern Church, serving as the Byzantine Empire’s main cathedral. It was converted into a mosque following the capture of Constantinople, now called Istanbul, by the Ottoman Empire in 1453.

It was included in the list of UNESCO World Heritage sites in 1985.

It first opened its doors as a museum in 1935, a year after the decision by Turkey’s Council of Ministers was approved by the founder of modern Turkey, Mustafa Kemal Ataturk. Since then, it has served as a symbol of both secularization as well as unity, being open to members of all faiths.

Friday’s ruling, however, has caused major waves throughout the international community, particularly among Orthodox leaders, who prior to the decision warned that reverting the Hagia Sophia into a mosque could have severe repercussions.

According to the Orthodox Times news agency, the Russian Orthodox Patriarchate said Friday they regret that their concerns and those of other Orthodox churches “has not been heard.”

“Unfortunately, this decision is not aimed at pacifying the existing disputes, but, on the contrary, it can lead to even greater divisions,” they said.

In a previous statement, Patriarch Kirill of Moscow and all Russia had said a reversal of the monument’s museum status could have political implications.

Kirill had insisted that the Russian Orthodox Church responds with “bitterness and indignation” to both past and present attempts to “degrade or trample upon the millennium-old spiritual heritage of the Church of Constantinople.”

“A threat to Hagia Sophia is a threat to the entire Christian civilization and, therefore, to our spirituality and history,” he said, adding, “To this day Hagia Sophia remains a great Christian shrine for every Russian Orthodox believer.”

“It is a duty of every civilized state to maintain balance: to reconcile the society, and not aggravate discords in it; to help unite people, and not divide them,” they said, implying that turning the Hagia Sophia into a mosque could have serious implications on Russia’s “dynamically” developing relationship with Turkey.

“One should take into account that Russia is a country with the majority of population professing Orthodoxy, and so, what may happen to Hagia Sophia will inflict great pain on the Russian people,” they said, insisting that the preservation of the monument’s museum status would “facilitate further development of the relations between the peoples of Russia and Turkey and help strengthen interfaith peace and accord.”

In a statement after the news, Secretary General of UNESCO Audrey Azoulay said she “deeply regrets the decision of the Turkish authorities, made without prior discussion, to change the status of Hagia Sophia.”

“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,” she said, adding that the Friday’s ruling, “raises the issue of the impact of this change of status on the property’s universal value.”

Noting that UNESCO had shared its concerns with Turkey through various letters as well as a meeting with the Turkish ambassador to UNESCO, Azoulay said that they found it “regrettable that the Turkish decision was made without any form of dialogue or prior notice.”

She urged Turkish authorities “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.”

In a June 30 homily during a divine liturgy, Patriarch Bartholomew of Constantinople, spiritual leader to roughly 300 million Orthodox Christians, said the neutrality of the Hagia Sophia was key to interfaith harmony in the region.

“As a museum, the Hagia Sophia can function as a place and symbol of meeting, dialogue and peaceful coexistence of peoples and cultures, mutual understanding and solidarity between Christianity and Islam, which is especially necessary,” he said.

Noting that it served as a place of Christian worship for some 900 and for 500 years was a place of worship for Muslims, he said it would be “unwise and harmful, in the 21st century,” for the Hagia Sophia, “which, due to its devotion to the Wisdom of God, makes the faithful of both religions meet and admire its greatness,” to be made into a source of “controversy and conflict.”

Converting the monument back into a mosque, he said, “will turn millions of Christians around the world against Islam, and the Hagia Sophia, which, because of its sanctity, is a vital center in which the East and the West are embracing, will break them up.”

“These two worlds – at a time when humanity, which is being tested and afflicted by the deadly pandemic of the new coronavirus – need unity and common orientation,” he said, lamenting the fact that, “Instead of uniting, a 1,500-year-old heritage is dividing us.”

“I am saddened and shaken,” he said, adding that Orthodox Christians “have survived for 17 centuries and we will stay here forever, as God wills.”

Similarly, Patriarch Theophilos of Jerusalem in a statement made ahead of Friday’s ruling said that given its tumultuous history, it was to Turkey’s credit that the Hagia Sophia had been administered as a museum for almost 100 years “in order to maintain an extent of neutrality.”

“Indiscriminate accessibility to the Hagia Sophia has borne fruit where there otherwise could have been further contention,” he said, calling in “a symbol of tolerance.”

Pointing to his own experience in the Holy Land, Theophilos said accessibility to major monuments and religious sites “promotes peace and mutual respect, whereas attitudes of exclusivity promote conflict and bitterness.”

In a statement issued on Friday, UNESCO noted that when the Hagia Sophia was inscribed on the World Heritage List as a museum, it entailed a number of legal commitments and obligations.

“Thus, a State must ensure that no modification is made to the outstanding universal value of the property inscribed on its territory. Any modification requires prior notification by the State concerned to UNESCO and then, if necessary, examination by the World Heritage Committee,” the statement continued.

“UNESCO furthermore recalls that effective, inclusive and equitable participation of communities and other stakeholders concerned by the property is a necessary condition for the preservation of heritage and for the enhancement of its uniqueness and significance. This requirement serves the protection and transmission of the outstanding universal value of heritage and is inherent to the spirit of the World Heritage Convention,” the UN organization said.

UNESCO called on Turkey to “engage in dialogue before taking any decision that might impact the universal value of the site.”

The Vatican has not commented on the decision, and several Orthodox publications, including the Orthodox Times, have criticized the pope’s “sad silence” on the issue.

This article has been updated with a statement from UNESCO.

Follow Elise Ann Allen on Twitter: @eliseannallen