It is a commonplace in historical scholarship that the English understanding of what occurred in Ireland in 1641 helped to shape the severity of the conquest and the land settlement visited on the country a er 1649. Among many other concrete connections, we have Oliver Cromwell’s own words from 1650: ‘we are come to aske an accompt of the innocent blood that hath been shed, and to endeavour to bring them to an accompt … who, by appearing in arms, seeke to justi e the same’.1 A decade later, those seeking to defend the recent dispossession of Catholic landowners and their transplantation to Connacht insisted that ‘since above 300,000 Protestants were murdered without provocation… who could blame them for putting those Irish … into such a part of the kingdom, as might most probably con ne them from the like wickedness in the future’?2 ere were countless other contemporary instances in which the alleged 1641 massacres were cited as justi cation for the treatment doled out to Catholics. Yet problems quickly arise if we attempt to discern exactly what information and precisely which publications informed the views and the policies of men such as Cromwell and bodies such as the English parliament.