After a long career teaching Byzantine and medieval history, notably at Princeton University and King’s College London, JH retired to pursue research, which is currently centred on the city of Ravenna and its anonymous Cosmographer.

She is attached to the Wittgenstein Project Moving Byzantium, based at the Austrian Academy of Sciences, Vienna, and maintains continuing membership of the Journal of Ecclesiastical History. the Advisory Publications Committee of the British School at Athens. Euro-Clio and the European Association of History Educators; Advisory Board of Symmeikta, Athens; Advisory Board of the Stavros Niarchos-Koç Center for Late Antique and Byzantine Studies, Koç University, Istanbul; Advisory Council of the Research Center for Byzantine Studies, Bogazici University, Istanbul. She was elected President of the Association Internationale des Etudes Byzantines, 2011-12, and is the Founding Editor of Translated Texts for Byzantinists, series published by Liverpool University Press. 

Selected publications

• Ravenna. Capital of Empire, Crucible of Europe (Penguin books 2021), Winner of the Duff Cooper Prize, shortlisted for the Wolfson History Prize.
• The Formation of Christendom, Princeton Classics reprint (Princeton University Press 2021)
• Byzantium, the Surprising Life of a Medieval Empire (Penguin books 2008)
• Unrivalled Influence. Women and Empire in Byzantium (Princeton University Press 2013)
• Margins and Metropolis. Authority across the Byzantine Empire (Princeton University Press 2013)

Expertise and public engagement

• Private Passions, BBC radio 3, December 2020
• In Our Time, BBC radio 4, March 2021
• Cheltenham Literary Festival, September 2020
• Hay literary festival May 2021
• Lahore Literary festival 2022
• Amos Anderson annual lecture, Rome, December 2020
• Church Conservation Trust lecture, January 2021
• Travellers Club Lecture
• Friends of the British School at Athens lecture
• Versus History podcast September 2021
• Bristol – Festival of the Future City, 2021
• All Saints Church, London W1, Celebration of Ravenna, 29 November 2021