Catherine McAuley was a lay Catholic woman of no fortune who spent twenty years as a companion in the Protestant household of William and Catherine Callaghan, who came in the end to trust her entirely. When William died in 1822 he left her his whole estate. She was forty-four, unmarried, and suddenly wealthy, and she spent it on a building.
The House of Mercy opened on Baggot Street on 24 September 1827: a house where poor girls could be taught, homeless servants could sleep, and sick women could be visited in their own rooms. Dublin's clergy were not uniformly pleased — a laywoman running a quasi-religious house was an anomaly, and she was pressed to regularise it. She did, reluctantly, and on 12 December 1831 she and two companions professed vows as the first Sisters of Mercy.
She had ten years left. In them she made ten more foundations in Ireland and England and set the character of the order: sisters who went out, walking the streets to the sick and the schools rather than staying behind a grille, which earned them the name 'the walking nuns'. She died at Baggot Street on 11 November 1841, and what she is remembered for saying that night is that the sisters should be sure to have a comfortable cup of tea when she was gone. There were a hundred of them then. There have since been tens of thousands, on every continent. John Paul II declared her Venerable on 9 April 1990.