His brother, Colonel Tiernan O'Rourke (1650-1702), fled Ireland after the Treaty of Limerick (1691) and served the Hapsburg Empire; he was killed at the battle of Luzzara in the Po valley in August 1702.
Brian MacDonagh of Ballindoon Castle, Co. Sligo became a Lady-in-waiting to Mary of Modena at the Jacobite court at Château de Saint-Germain-en-Laye outside Paris.
He obtained the Licentiate in Sacred Theology (Latin: Sacrae Theologiae Licentiatus; abbreviated STL) and lectured for a while.
There he arranged his consecration in Newgate jail by Patrick Donnelly, Bishop of Dromore, assisted by Edmund Byrne, archbishop-elect of Dublin, and Fergus O'Farrell (Ferral), archdeacon of Ardagh and Clonmacnoise.
No longer immune from prosecution, O’Rourke fled to the isolated area around Meelick friary in east County Galway and hid his identity under the name of Mr Fielding.
Bishop O'Rourke died, probably at Bellanagare, on 13 March 1735 and was buried at Creevelea Abbey near Dromahair in county Leitrim.
Among the family heirlooms of the O’Conor family at Clonalis House is O’Rourke's plain chalice (designed to screw apart for easy concealment), his liturgical vestments, a copy of a letter of safe conduct from Emperor Leopold I to Queen Anne relating to O’Rourke's return to Ireland as well as his pectoral cross and episcopal ring, the latter two believed to have been presented to him by Prince Eugene.