The school teaching workforce in Ireland has been characterised as White, Heterosexual, Irish-born, Settled and Catholic or WHISCS (Tracy, 2000 cited in Bryan, 2010. See also Clarke, 2009; Coolahan, 2003; Devine, 2005; Heinz, 2011; Hyland, 2012; Schmidt and Mc Daid, 2015). Data on those entering undergraduate and post-graduate initial teacher education programmes in Ireland (Keane & Heinz, 2015) and those seeking to enter the profession from abroad (Schmidt & Mc Daid, 2015; Mc Daid & Walsh, forthcoming) provide little evidence that this situation will change in the immediate future. This situation is not unique. Nevertheless, while it is accurate to claim that homogeneity is relatively consistent internationally (see Cochran- Smith, 2004), there exist a particular set of historical underpinnings to the development and maintenance of this phenomenon in the Irish context. Commencing with a brief overview of emerging qualitative and quantitative data establishing a stubborn homogeneity within the primary teaching workforce in Ireland, and further work which situates the Irish context within the wider European experience, this paper moves quickly to explain how the two most entrenched controlling factors maintaining this situation, religion and language, have deep historical trajectories. Drawing on critical documentary analysis, situated within a Critical Race Theory (CRT) framework, the authors argue that even since before the establishment of the national system of education in 1831, power brokers at various points in Irish history (e.g., British government, Irish government and various church authorities) have worked hard to control inclusion and exclusion from the primary teaching workforce. Through an indepth interrogation of legislation, state policy documents and ecclesiastical publications, the paper excavates very clear antecedents of, at various times, government and church authorities exercising strict regulatory authority over those to be imbued with the right to perform the highly moral act of reproduction of Irish society. In the context of an international landscape within which calls for a more heterogeneous primary workforce gain traction (see, for example, Schmidt & Block, 2010), this work has particular importance. Certain analyses (see, for example, Santoro, 2015; Keane & Heinz, 2015) emphasise paying attention to the complexities of teacher identity within the context of this broader push for diversification. This paper seeks to add another lay of understanding to this debate through unearthing pertinent historical technologies which secure the status quo.