After the conversion of Hagia Sophia from museum to a mosque a lot of Islamic and Pro-Erdogan news outlets claimed that Sultan Mehmed bought Hagia Sophia after he conquered Constantinople with photos of the supposed contract.
But in neutral sources (like Wikipedia) there is no mention of him purchasing Aya Sopha
Excerpt from Wikipedia: When Sultan Mehmed and his entourage entered the church, he ordered that it be converted into a mosque at once. One of the ʿulamāʾ (Islamic scholars) present climbed onto the church's ambo and recited the shahada ("There is no god but God, and Muhammed is his messenger"), thus marking the beginning of the conversion of the church into a mosque.Mehmed is reported to have taken a sword to a soldier who tried to prise up one of the paving slabs of the Proconnesian marble floor.
There is no mention of a purchase. So did he or did he not purchase Hagia Sophia before converting it into a mosque? If so what are the proofs to back it up?
This question came up a lot a few months ago when Hagia Sophia was in the news, and I tried to answer it here:
Did Mehmet The Conqueror buy the Hagia Sophia or take it by force?
The simple answer is no, there is no evidence that he did, and there is no reason that he would. I've been looking for more information ever since the discussion in that thread but I haven't found anything too useful. The supposed contract is, as far as I can tell, Mehmed's waqf endowment for the mosque, not a sales receipt of any sort.
The only other useful piece of information I've found is that there were legends about a Muslim hero who died in the first Arab siege of Constantinople 800 years earlier in the 7th century and was buried near the city. He prophesied that Hagia Sophia would one day be a mosque. So the Ottomans may have felt they were simply fulfilling a prophecy.
In addition to the sources in the previous question, I've also found:
Halil Inalcik, “The policy of Mehmed II toward the Greek population of Istanbul and the Byzantine buildings of the city”, in Dumbarton Oaks Papers 23/24 (1969/1970).
Halil Inalcik, “Istanbul, an Islamic City”, in Journal of Islamic Studies 1 (1990).
Gülru Necipoglu, “The Life of an Imperial Monument: Hagia Sophia”, in Hagia Sophia from the Age of Justinian to the Present, ed. Robert Mark and Ahmet Ş. Çakmak (Cambridge University Press, 1992)