founder of the Religious Sisters of Mercy (Mercy, Sisters of) (R.S.M.), a congregation of nuns engaged in education and social service.

With a legacy from her Protestant foster parents, McAuley, a Roman Catholic, commissioned a large building in Dublin. On Sept. 24, 1827, she opened it as the House of Mercy, an institution for the education of orphans and the poor. She and two companions took their vows on Dec. 12, 1831, officially forming the Religious Sisters of Mercy, with Catherine as superior until her death. In 1839 Mother McAuley established the congregation's first non-Irish house in London. Thenceforth, the Sisters of Mercy became one of the largest English-speaking congregations.