From Bishop David Moriarty's assertion in 1867 that hell was not hot enough to punish the Fenians, to Father James Chesney's alleged involvement in the I.R.A. Claudy bombings just over a century later, the Catholic church's relationship with Irish republicanism has been fraught with contradictions. The present thesis has examined this relationship for a time when republicans fought a guerrilla war against the British forces. It has looked at the attitude of priests to the use of political violence during the War of Independence from 1919 to 1921. Drawing from archival and printed sources, the thesis has constructed a picture of the clergy's response. Priests denounced the I.R.A. campaign in public comments, often threatening divine vengeance and a curse on those who committed or condoned violence against the Crown forces. But many priests also supported Sinn Fein and the Dail, and some helped the I.R.A. by concealing arms and ammunition and giving shelter to men 'on the run'. Priests also acted as 'chaplains to the forces' by providing spiritual support to the Volunteers, and a small number became actively involved in the guerrilla campaign. The thesis has concluded that priests were divided on the issue. There was little enough of a geographical pattern to priestly support, but priests in areas where violence was most common were more likely to condemn it than those in relatively peaceful areas. Moreover, clerical support was more frequently forthcoming from curates than from senior priests.