Catherine McAuley, an Irish Catholic laywoman, recognized the many needs of people who were economically poor in early nineteenth century Ireland and determined that she and women like her could do several things to relieve their suffering. With an inheritance she opened the first House of Mercy on Lower Baggot Street in Dublin, Ireland, on September 24, 1827 as a place to shelter, feed and educate women and girls.

Catherine's original intention was to assemble a lay corps of Catholic social workers. Impressed by her good works and wanting the work to continue after her death, the Archbishop of Dublin suggested that she establish a religious congregation.

On December 12, 1831, Catherine and two companions took their vows and returned to Baggot Street as the first Sisters of Mercy.