Recent scholarship has convincingly revolutionised the interpretation of Geoffrey Keating’s Foras Feasa ar Éirinn by introducing hitherto unregarded concepts of Renaissance humanism and of Counter-Reformation thought to the study of the Tipperary scholar-priest and his outstanding historical compilation. However, hardly any serious work has been carried out with regard to Keating’s polemical preface, written under the influence of these intellectual movements. The purpose of the present dissertation is to examine Keating’s disputes with a group of Tudor authors, from Stanihurst to Davies, whom he cites and challenges in this polemical preface to Foras Feasa. Keating strove to merge Irishness with Catholicism and provided the Irish Catholic nobility, denominated as the Éireannaigh, with a renewed origin myth to enhance their illustrious character. The exclusion of the aforementioned Tudor authors and the political and religious groups which they represented from the imaginary community of the Éireannaigh has tempted Irish historians to attempt to place Keating’s polemical preface in early Stuart political history. Nevertheless, in comparison to his political ideology, Keating’s methodological concerns enjoy a more prominent place in the refutation of the authors to whom Gaelic Ireland was foreign. By virtue of these methodological concerns, Keating is also comparable to contemporary antiquarians/historians, who produced similar national histories in the vernacular in the sixteenth and the seventeenth centuries. A further area of comparison, overlapping with this, is found in the historiography of the Catholic Reformation.