Judith Herrin is professor emeritus in the Department of Classics at King’s College London. Her books include Ravenna: Capital of Empire, Crucible of Europe; Byzantium: The Surprising Life of a Medieval Empire; Unrivalled Influence: Women and Empire in Byzantium; Margins and Metropolis: Authority across the Byzantine Empire; and Women in Purple: Rulers of Medieval Byzantium (all Princeton). She lives in Oxford, England.