Diarmaid Ninian John MacCulloch Kt FSA FRHistS FBA (/ˈdɜːrməd/; born 31 October 1951) is an English historian and academic, specialising in ecclesiastical history and the history of Christianity. Since 1995, he has been a fellow of St Cross College, Oxford; he was formerly the senior tutor. Since 1997, he has been Professor of the History of the Church at the University of Oxford. From Wikipedia