Erdogan's decision to return Aya Sofia to a mosque raises very interesting issues for both Christians and Muslims, if we are willing to face them honestly. Disclaimer: I am not making pronouncements here but raising questions to be answered by people smarter than me. 1/

First: there is a very strong opinion (perhaps the only opinion) in the classical Hanafi madhab that Sultan Muhammad Fathi did nothing wrong under Islamic law in seizing the Aya Sofia and converting it to a mosque when he conquered Constantinople. 2/ https://twitter.com/strwbmilksheikh/status/1281192268930711552?s=20

That is, under that opinion, since Constantinople was taken by conquest, he COULD have left the Hagia Sofia as a church, but was not obliged to. If the city had negotiated & the sultan had agreed to terms allowing it to remain a church, he would have been obliged to leave it. 3/

The underlying principle of this opinion is: there is nothing unjust in principle in repurposing or destroying the houses of worship of the conquered, but rather injustice exists only if the conquerers break an agreement struck as part of a surrender, not to harm them. 4/

Of course this opinion would not have seemed strange at all at the time. It was understood in pre-modern times that conquerers do what they please and that if there is any fault to be assigned, it is not lies with the conquered for being too weak to defend themselves. 5/

For example, is there any contemporaneous record of anyone, Muslim or Christian, objecting or being surprised that Spain converted the mosque of Cordoba to a cathedral when it defeated the Muslims in 1236? Other than the Muslims lamenting their weakness that led to the loss? 6/

Indeed, to this day religious and political leaders in Spain see absolutely no reason to restore the Cathedral of Our Lady of the Assumption to a mosque. And why should they? 7/ https://twitter.com/KhurramDehwar/status/1281650940576071680?s=20

Likewise as last as 1878 when the Ottomans surrendered Belgrade to Serbia, the Serbs destroyed or repurposed as churches all mosques but one, and did anyone find this strange, unexpected, or objectionable? 8/ https://twitter.com/JonathanACBrown/status/1281619795608244230?s=20

Pre-modern Christians and Muslims would have understood their enemies to be "wrong" in destroying one another's respective houses of worship only in this sense: that their enemies are blameworthy & inherently unjust because they opposed the true order of God on earth. 9/

That is, that the enemy is unjust for destroying their houses of worship in the sense that they represent falsehood and oppose the truth, but not because their actions are objectively wrong. 10/

So if Muslims accept the principle of the classical fiqh opinion that nothing is inherently unjust in destroying or repurposing the houses of worship of the conquered, they will not deem the conversion and destruction of mosques by Spain, Serbia, etc to be per se unjust 11/

Instead Muslims will recognize the destruction of these mosques by Spain, Serbia etc to be perfectly just and reasonable, and only wrong in the sense that their actions represent a victory for Satan & falsehood. And they will blame their own weakness. 12/

And Muslims will no longer be heard to complain that there the actions of Spain, Serbia etc are unjust in the sense of some objective principle of justice that the destruction of the houses of worship of the conquered is per se wrong, 13/

Likewise, to the extent that Christians reject the idea that there is anything wrong with the conversion of the Cordoba mosque to a church, they will also recognize Sultan Fatih (and Erdogan's) conversion of the Aya Sofia to a mosque to be entirely reasonable and expected, 14/

And in that case Christians will see the Muslims as guilty only in the sense that their actions represent the victory of falsehood and Satan, but not because there is anything per se unjust about destroying the houses of worship of the conquered. 15/

This is an attempt to be very clear about the first principles underlying our opinions on this issue so that we don't delude and muddle our thinking, & so none of us--Muslims or Christians--suffer from a lack of integrity in thinking about this. 16/

It now being clear what the first principles are here, an interesting question for Muslims & Christians is: is the assumption true beyond question that it is just to destroy or repurpose the houses of worship of the conquered, absent a treaty? 17/

Or is there some ground within our authoritative texts to presume that destroying the houses of worship of the conquered is inherently unjust? I don't know enough about the grounds for the Hanafi opinion cited above to know whether there is grounds for reconsidering it, 18/

nor am I qualified to suggest that it could or could not be reconsidered; or whether there is an alternative view within sunni tradition. If someone with that qualification can answer that I would be grateful. 19/

Likewise, I don't know enough about Catholic or Orthodox theology to understand whether there is some grounds for deeming the destruction or repurposing of mosques in Spain, Seria etc to be unjust, and thus worthy of being restored as mosques. 20/

I should add that, logically speaking, a view that destroying the houses of worship of the conquered is unjust is not in any way incompatible with the view that one's religion represents the one true order of God. 21/

That is, conceptually speaking, a religious civilization could see itself as representing divine truth on earth & see the other side's victory as wrong for precisely that reason, yet still have a theological basis for deeming it unjust to destroy their houses of worship. End.

To add to this, someone sent me this somewhat rough collection of varying opinions from the classical Islamic period and it includes that the places of worship of the conquered can be left alone if the ruler chooses, or perhaps should be left alone. https://justpaste.it/5ckf0 

I don’t vouch for the accuracy or completeness of this summary or its conclusion at the end (which appears to be a fatwa that I don’t know the anonymous compiler of this is qualified to make)