Complex sentence: Many of the Cappadocian Greek churches were converted in mosques after the Greeks left in populations exchange of the 1920s, these include the Church of St Gregory known today as "Buyuk Kilise Camii (Big Church Mosque)".
Split into simpler sentences: Many of the Cappadocian Greek churches were converted to mosques after the Greeks left in the population exchange of the 1920s. These include the Church of St Gregory known today as "Buyuk Kilise Camii (Big Church Mosque)".