This paper documents the introduction of the comprehensive schools in the Irish education system in 1963 and seeks to illustrate how the two most powerful organisations most directly involved in Irish education during this period, the Department of Education and the Catholic Hierarchy, viewed the introduction of the comprehensive schools. Through an in-depth analysis of existing correspondence between the Catholic Hierarchy and the Department of Education, this paper highlights the ongoing tensions between the Catholic Church and the government of the day in response to proposed changes in the Irish education system. The way in which the documents were written and presented provides a path of access to the mindsets of the participants in relation to the policy issue and processes that they were engaged in. Thereby this paper contributes to the historiography of the period and provides a new dimension through which Irish education policy can be understood at this juncture. (Contains 94 footnotes.)