Professor Micheál Ó Siochrú

Professor in Modern History

Research Interests

My primary research focus is on seventeenth-century Irish political, constitutional, urban and military history, from the Ulster Plantation to the Jacobite Wars, situated within a broader European and imperial contextual framework.

My research outputs divide neatly into two distinct, though overlapping, areas:

The first of these has involved the publication of important single-authored works with leading international presses and journals, resulting in the history of Early Modern Ireland, particularly the seventeenth century, increasingly enter the mainstream of international scholarly discourse and debate. This includes the recent publication of a chapter in the three-volume Cambridge World History of Genocide, which marked the culmination of twenty years of research on the nature of the English conquest of Ireland.
The second phase has involved a series of major international collaborative projects to produce critical editions online and in print of key archival material by exploiting/developing the latest computer technology. These include the 1641 Depositions, the Down Survey of Ireland, and most recently the letters, papers, and writings of Oliver Cromwell in three volumes for Oxford University Press. All these projects have attracted considerable competitive funding and resulted in a diversity of outputs, both for academic and public audiences.

Empire Project - Irish Research Council Advanced Laureate:
In 2023 I was one of only four scholars nationally in the Arts and Humanities to receive an Irish Research Council Advanced Laureate award for my latest project entitled ‘Empire: Cromwellian Ireland and the Transformation of the English Atlantic World’. This project engages with the expansive global scholarship on empire and colonialism, exploring for the first time Ireland's key role in propelling England from a minor European state in the early seventeenth century into the major world power by the mid-eighteenth century. The project is also developing new Artificial Intelligence (AI) and Natural Language Processing (NLP) technology for the transcription of, and engagement with, early modern documents.

Select Publications

Books

God’s Executioner: Oliver Cromwell and the conquest of Ireland (London: Faber & Faber, 2009), pp. 316.
Confederate Ireland, 1642-1649: A constitutional and political analysis (Dublin: Four Courts Press, 2008, 2nd edition), pp. 295.

Edited Sources

New Down Survey of Ireland website (2026) – https://www.downsurvey.ie/.
English translations of Archives Nationales d'Outre-Mer: Martinique correspondence, COL C8 A 1 1663-1683 (Zenodo, 2025), with David Brown.
The Letters, writings, and speeches of Oliver Cromwell, Vol.2 (1649-1653), (eds) Micheál Ó Siochrú; Elaine Murphy; Jason Peacey (Oxford, Oxford University Press, 2022), pp.1-823
The 1641 Depositions, vols. 1-9, with three final volumes to be published 2026, (eds), Aidan Clarke, Micheál Ó Siochrú, Jane Ohlmeyer, Tom Bartlett, and John Morrill (Dublin, Irish Manuscripts Commission, 2014-25). See online version at https://1641.tcd.ie/.

Edited Volumes

Ireland, 1641: Contexts and Reactions – with Jane Ohlmeyer – (Manchester University Press, 2013, 2nd edition paperback, 2015), pp.286.
The plantation of Ulster: Ideology and Practice – with Éamonn Ó Ciardha – (Manchester University Press, 2012, 2nd edition paperback, 2014), pp.304.
Forging the State: European state formation and the Anglo-Scottish Union of 1707 – with Andrew Mackillop – (Edinburgh, Edinburgh University Press, 2009), pp.210.
Kingdoms in Crisis: Ireland in the 1640s: Essays in honour of Dónal Cregan (Editor. Dublin: Four Courts, 2000), pp.288.

Journal Articles/Book Chapters

‘Extirpation and annihilation in Cromwellian Ireland’, in Ned Blackhawk, Ben Kiernan, Benjamin Madley, Rebe Taylor (eds), The Cambridge World History of Genocide, vol.2, Genocide in the Indigenous, Early Modern and Imperial Worlds, from c.1535 to World War One (Cambridge, Cambridge University Press, 2023), pp.163-185.
‘Rebuilding the past: The transformation of Early Modern Irish history’, The Seventeenth Century, vol.34, issue 3 (2019), pp.381-404.
'The Down Survey and the Cromwellian Land Settlement' in Jane Ohlmeyer (ed.), The Cambridge History of Ireland, vol.2, 1550-1730 (Cambridge, Cambridge University Press, 2018), pp.584-607 [with David Brown].
‘The centre cannot hold: Ireland 1643-1649’, in Michael J. Braddick (ed.), The Oxford Handbook of the English Revolution (Oxford, Oxford University Press, 2015), pp.137-53.
'Civil autonomy and military power in early modern Ireland, Journal of Early Modern History, vol.15 (2011), pp.31-57.
‘Atrocity, codes of conduct, and the Irish in the British Civil Wars, 1641-1653’, Past and Present, no.195 (2007), pp. 55-86.
‘Propaganda, rumour and myth: Oliver Cromwell and the massacre at Drogheda’, in David Edwards, Pádraig Lenihan and Clodagh Tait (eds), Age of Massacres: Violent death in Ireland, 1550-1650 (Dublin: Four Courts Press, 2007), pp.266-82.
‘The duke of Lorraine and the international struggle for Ireland, 1649-1653’, The Historical Journal, vol.48:4 (2005), pp.905-32.
‘Confederate Catholics and the constitutional relationship between Ireland and England, 1642-49’, in Ciaran Brady and Jane Ohlmeyer (eds), British Interventions in Early Modern Ireland (Cambridge: Cambridge University Press, 2005), pp.207-29.

Teaching and Supervision

I teach several modules on early modern Ireland. These include Freshman (Years 1 & 2) survey modules on Early Modern Ireland, 1500-1800. At the Sophister level (Years 3 & 4), I teach modules on Confederate Ireland (1641-1660), the 1641 Depositions, and Oliver Cromwell. I also teach modules on the war in the north of Ireland in the second half of the twentieth century, including an interdisciplinary module entitled, ‘Reimagining Northern Ireland’. At MPhil level, my teaching focuses on seventeenth century Irish, European and imperial history. I welcome postgraduate research students interested in any aspect of early modern Irish and imperial histories.