This work details traces the origins, development and impact of the proselytizing organization, the Society for Irish Church Missions to the Roman Catholics, from its Protestant foundation during the famine of 1845–47 to the early decades of Irish Free State. It argues that the foundation of this ostensibly religious society was also underpinned by social, political, and economic factors and demonstrates that by the mid 1850s the mission operated on a very substantial scale.Moffitt examines the mission’s role in the shifting political realities of the late nineteenth and early twentieth centuries. The impact of this inter-faith power struggle and its legacy to the present day are explored by examining contemporary sources, folklore evidence, and the depiction of proselytizing missions in both Catholic and Protestant denomination literature and fictional writings.