The butcher of Constantinople?
His soldiers plunder the city, slaughtering large number of Christians, without distinction for children or women, desecrating churches. A large number of people went to Haghia Sophia hoping that they won’t be touched, but the Turks went in and killed everybody there.
Later he converted the largest and the finest church, Haghia Sophia, into a mosque.
As a result of Muslim oppression after the conquests Christians started disappearing from Middle East. And they continue to disappear as ISIS continues a long tradition by killing and raping Yazidies and Christians today in Syria.
PS The real history is not as nice as your side usually tells you.