Adèle Euphrasie Barbier was born at Caen, Normandy, France, on 4 January 1829, the child of Louis-Désiré Barbier, a shoemaker, and his wife, Jeanne Adèle Le Cler. She worked for a time as a laundress before entering religious life.
In 1848 she joined a small, recently founded religious order, the Sisters of Calvary (affiliated to the Servite order). In 1851 she was part of a group sent to London to learn English as a prelude to work on the mission field. The sisters, now known as the Institute of Compassion, established a religious house and became involved in the running of parish schools. Sister Maria, as she became, trained as a teacher and became the novice mistress. Problems developed when she felt that the order had lost sight of the missionary work which had first drawn her. She was removed from the position, perhaps because of her austere and ascetic spirituality.
Barbier attempted to transfer to the Marist sisters, without success, but this brought her into contact with the Marist fathers, based in Lyons. In 1861 she was invited by J.-M. Favre, their superior general, to respond to Bishop P. J. Viard's request for a sister to take charge of a school in Wellington, New Zealand. Although this need was subsequently met by the Sisters of Mercy, Barbier was asked to stay on in Lyons to help form a new group of nuns to assist the Marist missions in the south-west Pacific. A number of volunteer laywomen who had already gone to work in the mission were to be incorporated in the new congregation. Barbier took a new name in religion, becoming Mother Marie du Coeur de Jésus (Mary of the Heart of Jesus), and developed the Congregation of Our Lady of the Missions. She devoted herself to recruitment, training and fund-raising.
Barbier was austere and deeply spiritual, and committed herself to extreme mortifications, wearing a hair shirt and chains. She drew up rules for her order, including enclosure, where visitors were spoken to through a grille. The Marist fathers believed that this was inappropriate in the mission field. Barbier appealed to Rome to settle the dispute and the autonomy of the new congregation was confirmed. However, the sisters already placed in the Wallis Islands and Samoa were withdrawn and did not return in Barbier's lifetime.
Barbier first visited New Zealand in 1872, at the beginning of a 3½-year stay in the Pacific, during which she travelled incessantly, despite poor health and a tendency to seasickness. She arrived in Lyttelton in December 1872 on the Albion, via Campbelltown (Bluff) and Dunedin. From a base in Christchurch she visited Nelson and Napier in 1873. In October 1883 she was again in New Zealand, arriving from India where she had spent a few months. From Christchurch she paid visits to New Plymouth in 1883 and Ashburton in 1884 to set up foundations, and visited the community of her order in Hamilton. In May 1885 she set up a foundation in Pukekohe. She narrowly survived a coach accident between Napier and Wellington, and left New Zealand from Napier in May 1886. By this time there were 92 sisters in New Zealand, with nearly 1,500 children in their schools and orphanages.
Zealous and ascetic, Barbier was able to attract recruits and keep them, winning the devotion of her spiritual daughters with her affection and individual concern for them. Her relations with priests and bishops were more stormy: Bishop Francis Redwood, while admiring her dedication, objected to her authoritarianism and rigidity.
Barbier was a woman of strong personality, determined to maintain her independence to develop and direct her institute free of detailed supervision by local bishops. The Sisters of Our Lady of the Missions made a major contribution to both Māori and Pākehā education. Eight houses were founded in New Zealand in Barbier's lifetime, beginning with Napier in 1865. Houses were founded in Christchurch in 1868 and Nelson in 1871, and a New Zealand novitiate established in Christchurch in 1873. A school for Māori girls was established at Napier in 1867, as well as houses at New Plymouth (leading to a legal dispute which left the order in debt for many years), Ashburton, Pukekohe, Hamilton and Ōpōtiki.
Mother Mary of the Heart of Jesus died at her order's house, St Ann's convent, at Westbere, Kent, England, on 18 January 1893. There are nearly 2,000 sisters in the international Congregation of Our Lady of the Missions, over 200 of whom work in New Zealand, where the order still runs six secondary schools for girls.