Greece has appealed to UNESCO to intervene after Muslim prayers were read at Hagia Sophia in Istanbul on Wednesday, provoking the religious sentiments of Christians around the world.

In a meeting Thursday with UNESCO Assistant Director-General for Culture Francesco Bandarin, Alternate Foreign Minister Yiannis Amanatidis said the prayers at Hagia Sofia, which were broadcast on television and attended by government officials, were insulting to Christians, and compromised the monument’s cultural significance.

Francesco Bandarin said that “UNESCO has already told Turkey that the monument must remain a cultural monument, and that the organization will repeat the same message to Turkish authorities”.

Hagia Sofia was commissioned in the 6th century by the Byzantine emperor Justinian, and was one of Christendom’s great churches before it was converted into a mosque after Constantinople was conquered by the Ottoman Turks in 1453. In 1935 it became a museum.