By the 1590s, both Hugh O'Neill and English crown administrators had every right to think that a war fought in the name of the Catholic Church would rouse the Old English population of the Pale from passive recusancy to armed revolt. A ‘faith and fatherland’ ideology had struck roots in Ireland long before the outbreak of the Nine Years’ War. It had found early expression in the revolts of James Fitzmaurice (1579), Viscount Baltinglass (1580), and William Nugent (1581). Not only had the Old English leaders of these uprisings espoused a Catholic cause, but their actions and assertions had been bolstered by the ministries of Counter-Reformation clerics who openly denounced English heresy and solicited foreign intervention for Ireland. These clerics were some of the earliest proponents of an Irish ‘faith and fatherland’ philosophy and they would come to be regarded as the chief propagandists of the nationwide revolt led by Hugh O'Neill. How this came to be and how the work of the clergy became coterminous with the ideological wing of O'Neill's rebellion is crucial to understanding the Nine Years’ War and the predicament of Ireland's Catholic inhabitants. The involvement of Catholic clerics gave many administrators cause to fear the kind of religious fervour they might inspire, and this anxiety was clearly articulated in official records. This chapter will therefore examine the activities of some of O'Neill's chief clerical conspirators to illustrate that O'Neill's hopes and administrators’ concerns were not groundless. However, it will also challenge the assumption that an appeal for a Catholic crusade would find wide and enthusiastic support in Ireland, and especially amongst the population of the Pale. Although religious concerns are clearly apparent in the State Papers, evidence suggesting that religion and the Catholic clergy played a decisive role in this conflict is inconclusive.