The sad reality of our fallen nature is that oftentimes peace must be bought with a sword. That isn't to diminish the power, efficacy, or necessity of prayer. Just that history bears out few examples where prayer "alone" turned back evil.
The sad reality is that the Church has often not transcended that fallen nature; has acquiesced and conspired with emperors to build empires not her own.
Yes, it’s an effrontery to see church treasures turned into mosques. On the other hand, a number of hierarchs and religious orders have taken profits from developers eager to turn abandoned, but quaint churches and monasteries into condominiums, hotels and pubs!