The Sisters of Mercy came to Callan from Athy in December 1872, at the invitation of the Bishop of Ossory, Dr. Patrick Moran, and took up residence in Callan Lodge, later named St. Mary's Convent.
The Bishop's first objective in bringing the Sisters to Callan was to help in restoring peace and tranquility to the parish, torn as it was by strife and division, resulting from the Callan Schism. Bishop Moran placed his hopes in the Sisters that by their prayers, visitation of homes, and devoted service of the sick and suffering, they would "soften the hearts of the people and win them back to the fold." He also hoped that the Sisters would undertake the education of girls, which at that time, unlike that of boys, was sadly neglected.(The Christian Brothers came to Callan in 1867)
On their arrival in Callan, the Sisters faced strong opposition and even open hostility from those hostile to the Official Church
In those days, Callan was a poverty-stricken town and many eked out a marginal existance. Unemployment and poverty led to malnutrition, which in turn, resulted in much sickness, particularly T.B. A few days after their arrival, the Sisters began their Apostolate of Visitation. They visited the homes of the poor and the sick, prepared children and adults for the reception of the sacraments and gave Religious instruction. At first many doors were closed against them, but little by little they won the hearts of the people and very soon the town and surrounding areas welcomed them with open arms.