In 1888, Dunlop was elected to a Bishop Berkeley Fellowship of Owens College, worth £100 a year for two years, to support original research, and was encouraged by Adolphus Ward to continue with the history of Ireland as his field of study. His first significant work was to make a calendar of the documents in the Irish Record Office relating to the Cromwellian settlement of Ireland, plus some from Trinity College, Dublin. This work remained unpublished until 1913, but was made available to scholars in manuscript.