I welcome dissertation enquiries in the field of medieval history c.1000-1400, particularly the social, military, landscape, political and legal history of Britain and the crusader states.

I am Reader in Medieval History, Deputy Director of the Centre for War and Diplomacy (CWD), and a Research Fellow at The Ruskin. I work on the social history of war in medieval Britain c.1100-1400, investigating the experiences of low-status combatants and war-torn populations, and shifting patterns of thought concerning personal responsibility in conflict. Here and through the CWD, I am interested in combining insights from other disciplines and historical periods. This builds on my previous research on the ethics and practice of war, politics, rebellion and revolution in medieval Britain. I hold a Philip Leverhulme Prize in History (2020) and in Michaelmas 2022 was a Visiting Fellow at All Souls College, Oxford. I enjoy writing for and speaking to a broad public audience through TV, radio and print.

With interests spanning the central and later Middle Ages in the Atlantic Archipelago and across Christendom, my research investigates the experiences of low-status combatants and war-torn populations in Britain c.1100-1400, and shifting patterns of thought concerning personal responsibility in conflict. Its goal is to excavate the archival and physical remnants of wartime experience across the period’s civil and inter-polity conflicts – drawing from social, legal, material and landscape history, cross-chronological insights, and other disciplines (notably archaeology, anthropology, philosophy and law) – to build a new social history of war from the ground up.  It incorporates extensive new archival research and investigation of conflict landscapes, including those at Evesham (Worcestershire) and Lowther (Cumbria). This research will lead to my third book (recent and forthcoming articles and media can be found below).

This builds on my previous research on the ethics and practice of war, politics, rebellion and revolution in medieval Britain. My second monograph explored the life of Simon de Montfort earl of Leicester (d.1265), who seized power from King Henry III and established a council to govern with the help of parliament: England's first revolution. Simon amassed a vast popular following, many of whom died with him at the Battle of Evesham fighting as avowed crusaders. The Song of Simon de Montfort: England's First Revolutionary and the Death of Chivalry was published by Picador in May 2019 in the UK and Commonwealth, with publication in the USA following with OUP in September 2019. My first monograph, Bishops in the Political Community of England, 1213–1272, was published with OUP in January 2017. This explored the role of bishops in rebellion and revolution in thirteenth-century England, looking at the interaction of political thought and action in the age of Magna Carta and the Montfortian revolution,

In 2020, I received a Philip Leverhulme Prize in History and, in 2022, was a Visiting Fellow at All Souls College, Oxford. At Lancaster, I am Deputy Director of the Centre for War and Diplomacy (taking up the role of Director in 2024), and from 2024 the Director of Education and Curriculum Transformation in the Department of History.

I'm a Fellow of the Royal Historical Society and secretary of the Pipe Roll Society, and enjoy writing for and speaking to a broader public audience, whether through talks or TV, radio and print. 

I joined Lancaster in 2017; previously I was at the University of East Anglia, where I was a researcher on the AHRC's Magna Carta Project, and from 2012-13 I was a researcher on the People of Northern England databse 1216-1286, part of the AHRC's Breaking of Britain project, which explored the period leading up to the Scottish Wars of Independence. I undertook my PhD at King's College London with joint supervision at University College London, and was Thornley Fellow at the Institute of Historical Research. 

I am currently working on four projects.

• My major ongoing project investigates the experiences of low-status combatants in the later Middle Ages, and shifting patterns of thought concerning personal responsibility in conflict. Funded by a Philip Leverhulme Prize, it incorporates extensive new archival research and investigation of conflict landscapes. It will lead to a new book, with preliminary articles and chapters appearing in 2023-24 (see 'Current Research', below).
• Lowther Medieval Castle and Village is an archaeological and archival investigation of the origins and biography of the medieval castle and attached settlement at Lowther in Cumbria, which potentially date to the eleventh or twelfth century – a transformative but little-documented era in Cumbria's past. The project is funded by the Castle Studies Trust and brings together Lancaster University, Lowther Castle and Gardens Trust, UCLan, and Allen Archaeology.
• Archives of the Borderlands, with Prof Fiona Edmonds at Lancaster, investigates the extensive medieval archives of three houses on the Anglo-Scottish border: Alnwick, Howard and Lowther. It is funded by the Friends of the Cumbria Archive Service.
• 'The Records of the Medieval Duchy of Lancaster' investigates the medieval origins of the Duchy of Lancaster, and is a collaboration involving the University of Lincoln, Lancaster University (including its Regional Heritage Centre), the University of Cambridge and The National Archives (UK). It incorporates two projects at Lancaster (with Fiona Edmonds): ‘The Duchy of Lancaster’s Lancashire Records, 1267-1348’, funded by the Society of Antiquaries of London, and ‘Settlement and Landscape in Medieval Lancashire: The Records of the Forest Justice’, funded by the Medieval Settlement Research Group.  

Publications forthcoming in 2024 include:

• S.T. Ambler, 'The Dark Trophies of the Battle of Evesham, the Northumbrian Cult of Simon de Montfort, and the War of the Welsh Marches (1264-5)', accepted 2022 by English Historical Review; publication 2024.
• S.T. Ambler, 'The Common Law and Civil War in Fourteenth-Century England: The Prosecution of Treason and Rebellion under Edward II, 1322-1326', accepted by The Journal of Legal History, for publication in 2024.
• S.T. Ambler, 'Latin Christendom in the Later Middle Ages, c.1000-1500' in Isabelle Duyvesteyn and Beatrice Heuser (eds.), The Cambridge History of Strategy Volume I, for publication in 2023-24.

BBC2: Digging for Britain (S11E1) discussing Lowther medieval castle (Cumbria)

Channel 4: Bone Detectives: Britain's Buried Secrets (S1E3: A Hampshire Cemetery)

History Hit: Rebellion in the North (Ep1, 'The Harrying of the North')

Channel 4: Walking Through History (S4E5, 'King John's Ruin')

BBC Radio 4's In Our Time: The Second Barons' War

BBC History Extra podcast: 'Simon de Montfort's Medieval Revolution'

Cabinet Office podcast with Leader of the House of Commons Jacob Rees-Mogg MP, 'Why Parliament Works'

BBC History Weekend: 'Simon de Montfort and England's First Revolution'

Rex Factor podcast (extended discussion): Simon de Montfort

Herstory Club: Interview (June 2021)

• Co-convenor of the Late Medieval Seminar at the Institute of Historical Research.
• Secretary of the Pipe Roll Society. 
• Trustee of Lowther Castle and Gardens Trust. 
• Member of the AHRC-funded research network Noblesse Oblige? 'Barons' and the Public Good in Medieval Afro-Eurasia.
• Member of Steering Committee, Northern Network for the Study of the Crusades.

For enquires about the modules 'From Rebellion to Revolution: The War for the Throne, 1199-1265' (HIST316) and 'Warfare in the Medieval World, 1100-1500' (HIST444), please contact Dr Lorenzo Caravaggi.  

New module for 2024-25: 'Death: From the Fall of Rome to the Reformation’ (HIST216). What does it mean to die? Does it hurt? Is it frightening? Will I see those I love again? What does it mean to kill, whether an enemy, a friend, or myself? Death is a universal human experience, a cataclysm, triumph or adventure we all confront. But how we do that has varied vastly across history. In the European Middle Ages, the Church’s doctrines shaped ideas of death, from burial in the consecrated ground of churchyards to the theology of heaven, hell and purgatory. The living and the dead were a community: those on earth could speed the dead through their passage in the afterlife, and those in heaven could intercede for the living. Yet at the margins lay a shadowy world, in which the restless dead returned to haunt those left on earth, and the despairing took their lives in an act known as ‘self-murder’. In this module, we explore varied experiences of death across the medieval centuries in the Christian West, from end-of-life care to execution, and from battlefields to the Black Death. And we discover the different means of investigating death, from the chronicles that describe the walking dead, to the archaeology of burial practice, and from murder trials to palaeogenetics, unlocking the passage of disease. This is, by nature, a disturbing field of study. But what we learn cuts to the heart of what it means to be human – in the past and today.

Fellow of the Higher Education Academy