sentences:  From 1976 until 1997 he was also lecturer in medieval history at Merton College.He was Slade Professor of Fine Art for the academic year 1987–88 and in 1993 he was named university reader in medieval history.In 1997 he became the first Roman Catholic and the first layperson to be appointed Regius Professor of Ecclesiastical History in the University of Oxford and consequently he became the first lay canon of Christ Church Cathedral.