Born in London, Hallahan was the only child of poor Irish Catholics. Due to the illness of her parents, when she was six years old she was sent to an orphanage, St Aloysius's Charity School in Somers Town, for three years and then at the age of nine went out to service, in which state of life she remained for nearly thirty years. In 1826 she accompanied the family with which she was living to Bruges; there she tried her vocation as a lay sister in the convent of the English Augustinian nuns, but only remained there a week.[1]
She became a Dominican tertiary in 1842, and then came to England, proceeding to Coventry where she worked under William Bernard Ullathorne, afterwards Roman Catholic Bishop of Birmingham, among the factory girls. Presently she was joined by others, and with the consent of the Dominican fathers formed a community of Dominican tertiaries, who were to devote themselves to active works of charity.[citation needed]
The rule of the Third Order of St. Dominic, being intended for persons living in the world, was not suited to community life; she therefore drew up, from the rule of the first and second orders, constitutions which she adapted to her own needs. The first professions were made on the feast of the Immaculate Conception, 1845. From Coventry the community moved to Bristol, where several schools were placed under their charge, from there they went to Longton, the last of the pottery towns in Staffordshire.[citation needed]
In 1851 her congregation received papal approbation, and in 1852 the foundation stone of St. Dominic's convent was laid at Stone, Staffordshire, outside the Black Country: this became the mother house and novitiate, and to it the Longton community afterwards moved. This Stone convent at one time enjoyed the reputation of numbering some of the cleverest women in England among its subjects, of whom the late mother provincial, Augusta Theodosia Drane, was one.[citation needed]
At Stone a church and a hospital for incurables were built; this latter was one of Mother Margaret's schemes, and was begun on a small scale at Bristol. In 1857 she opened another convent at Stoke-on-Trent, a few miles from Stone, and the same year founded an orphanage at the latter place.[citation needed]
In 1858 she went to Rome, to obtain the final confirmation of her constitutions, which was granted, and the congregation was placed under the jurisdiction of the Master General of the Dominicans, who appoints a delegate, generally the bishop of the diocese, to set for him. New foundations were made at Our Lady and St Catherine of Sienna next to Grove Hall in Bow, London, where Mother Margaret donated a relic of the Saint, and at St Marychurch, Torquay, before her death.[citation needed]
