The Hagia Sophia Museum in Istanbul, which is going to be converted into a mosque by the decision of the Turkish government, is one of the oldest historical buildings in Turkey, which was built as a church about 15 centuries ago. About 900 years later, the Ottoman government turned this church into a mosque after conquering Istanbul. But finally, after the establishment of the Republic of Turkey during the reign of Kemal Atatürk, this historical building was turned into a museum .