This study explores, reconstructs and evaluates the social, political, educational and economic worlds of the Irish Catholic episcopal corps appointed between 1657 and 1829 by creating a prosopographical profile of this episcopal cohort. The central aim of this study is to reconstruct the profile of this episcopate to serve as a context to evaluate the ‘achievements’ of the four episcopal generations that emerged: 1657-1684; 1685-1766; 1767-1800 and 1801-1829. The first generation of Irish bishops were largely influenced by the complex political and religious situation of Ireland following the Cromwellian wars and Interregnum. This episcopal cohort sought greater engagement with the restored Stuart Court while at the same time solidified their links with continental agencies. With the accession of James II (1685), a new generation of bishops emerged characterised by their loyalty to the Stuart Court and, following his exile and the enactment of new penal legislation, their ability to endure political and economic marginalisation. Through the creation of a prosopographical database, this study has nuanced and reconstructed the historical profile of the Jacobite episcopal corps and has shown that the Irish episcopate under the penal regime was not only relatively well-organised but was well-engaged in reforming the Irish church, albeit with limited resources. By the mid-eighteenth century, the post-Jacobite generation (1767-1800) emerged and were characterised by their re-organisation of the Irish Church, most notably the establishment of a domestic seminary system and the setting up and manning of a national parochial system. Significantly, it was with the post-Jacobite generation of bishops that the Irish episcopal corps emerged as, arguably, the most independent episcopate in Europe. After the Act of Union (1801) a new generation of bishops emerged that was characterised by an episcopate largely drawn from a lower socio-economic background and who were appointed due to merit rather than family affiliation or ecclesiastical patronage.