The revolutionary activities of the Irish Republican Brotherhood in the mid-nineteenth century posed an enormous challenge to both the Catholic Church and the state in Ireland. The Fenians not only undermined ecclesiastical authority but also sought to create a society in which church and state would be completely separate.

By contrast, the British state, although ostensibly hostile to Catholicism, nonetheless tried to use ecclesiastical authority as an instrument for the preservation of the political status quo and as a means to curb the subversive propensities of the Church's adherents. Although Church and state worked towards the same end the eradication of Fenianism - there was, ironically, little direct cooperation: proof positive of their mutual suspicion. That said, both Church and state laboured for the papal condemnation of Fenianism in 1870.

However, by then, Fenianism had effectively changed the terms of the political debate in Ireland and, ultimately, neither ecclesiastics nor governments were able to contain the ideological forces released by the Fenian organization.