The Sisters of Mercy are a Roman Catholic community of women religious founded by Catherine McAuley in Dublin, Ireland, in 1831. Dedicated to God and the works of mercy, the order quickly expanded, ultimately reaching North, Central and South America; England; Australia; New Zealand; the Caribbean; Micronesia; Southeast Asia; and parts of Africa.

Sisters of Mercy first came to the United States in 1843. Led by Mother Frances Xavier Warde, a group of seven Sisters of Mercy from Ireland arrived in Pittsburgh, Pennsylvania, and founded the first Mercy convent in the United States. Mother Frances Warde went on to establish more foundations in the United States and soon other Sisters of Mercy from Ireland followed, establishing numerous additional foundations throughout the Americas.

Because travel and communication were difficult in the 1800s, it made sense for each Mercy foundation to become an independent congregation with its own governance. Although all of the Mercy congregations at the time shared a common history and charism, each developed slightly uniquely so as to best serve the people of God in a particular geographic location.

In 1918 a papal directive invited all religious congregations to review their constitutions. This review revealed the growing distinctiveness in the interpretation of the Mercy charism. Several Mercy superiors wondered that if this trend continued, the result would be the loss of a unified charism shared since the days of Catherine McAuley.

“Many superiors could visualize only one alternative: if uniformity of rule and custom was to be preserved, it was expedient to establish a generalate and have one revision of the rule and constitutions for all.” (36, The Amalgamation, Sister Justine Sabourin, RSM)

Mother Mary Carmelita Hartman, the Mother Superior in Baltimore, Maryland, emerged out of preliminary unification discussions and planning as the leader of the movement to form a single system of government. Her initiative to unite as many of the Mercy congregations as possible led her to being elected the first Mother General of the Sisters of Mercy of the Union. The Sisters of Mercy of the Union, formed in 1929, ultimately organized almost 50 motherhouses into six provinces while 16 remained independent. In retrospect this unification of so many Mercy congregations was the first step towards the journey of oneness that continues to this day.