In the second half of the 16th century, the advocates for tolerance gain momentum. An important figure was Sebastian Castellio, who lived in Geneva and Basel. He became well renowned for his reproach of John Calvin, who had Michael Servet executed for the denial of the Trinity. In Castellio’s writings, we see the arguments for tolerance being systematised. In Castellio also, the Ottoman Empire is the most prominent example of a nation where the diversity of religions proves to be succesful:

Wherever there are persecutions everything is full of disturbance. On the contrary where there are no persecutions, everything is tranquil in spite of diversity of religion. I know some cities in which there are almost as many opinions as heads, but because there is no persecution, there is no sedition, and should persecution commence all would be in disturbance. At Constantinople there are Turks, there are Christians, and there are also Jews, three peoples widely differing from one another in religion. Nevertheless they live in peace, which certainly they could not do if there were persecution. A careful investigation will reveal that persecutors have always been the cause of great troubles. Wherefore, Princes and Magistrates, if you desire peace and tranquillity, do not listen to those who incite you to persecution, for they are seditious, however much they accuse others of sedition, as the Jews accused Christ, though they were themselves responsible. The dwelling of Christ must be built by love. The persecutors wish to build it by hate and blood.

Indeed, Castellio mentions Ottoman Constantinople as the only example of the ‘cities’ he knows of, and likens it to the ‘dwelling of Christ, built by love’. 

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This is an excerpt from the article ‘Let the Muslim be my Master in Outward Things’, on Islamic influences on the emergence of tolerance in Europe. Download the complete article from Al-Islam eGazette, January 2010.