St. Mary's Church has been under the care of the Order of Preachers, commonly known as the Dominicans, since 1886. Dominicans at St. Mary's serve the Parish, the Shrine of the Infant of Prague, as staff for the Knights of Columbus, as seminary professors, as chaplains for Our Lady of Grace Monastery of Dominican Nuns in North Guilford, and as preachers and spiritual directors in the New Haven area. The Friars are members of the Province of St. Joseph, based in New York City. The Province was established in 1805 and has over 250 Friars who are engaged in parish ministry, campus ministry, foreign missions, retreat work, and education, and also operates Providence College in Rhode Island. The present priory building was erected in 1907, and provides an environment for prayer, study, silence, and community life, for the Dominicans.

The Lord Jesus Christ entrusted the mission of preaching to the twelve apostles. St. Dominic de Guzman restored the preaching ideal of Jesus Christ and his twelve apostles by establishing the first apostolic Order in the Church. This Order would provide a new dimension to ministry by making preaching frequent within the Church. It would give new direction to monasticism by combining contemplation with an active apostolate to serve the Church in a specific purpose.

St. Dominic de Guzman, the son of a Spanish noble, was born in Calaruega, Spain. After studying with his uncle who was a priest, and at the University of Palencia, he joined the Canons (priests living together under the discipline of a rule) of the Cathedral in Osma, Spain, and was ordained a priest.

Dominic and the bishop of the diocese, Diego, traveled through the south of France on a diplomatic mission in 1204. There they found the Church devastated. The Albigensian Heresy (named after the town in France where it originated) was rampant. Many people had accepted a doctrine that viewed material creation as evil and, therefore, rejected the idea of the Word-made-flesh, marriage, and the sacraments. Many clergy were helpless to stop it because they were uneducated and materialistic.

Dominic's response was to provide the Church with a group of preachers who would be learned, disciplined, and poor. He adopted traditional customs and practices in the Church and formed them into a specific way of life. Through the profession of vows the friars would embrace the community life of the early Church. They would imitate the first apostles who left behind their possessions and property to dedicate themselves to prayer and the Word of God. The friars would be learned and educated through study as a basis for fruitful preaching. The friars would observe liturgical prayer sung in community like monks and would draw from it their active ministry.

With the approval of the Pope Honorius III in 1216, the friars would carry out the task entrusted by Christ to the Apostles: to preach. Until this time the tasks of preaching and teaching were reserved to the bishops as the successors of the apostles. The preaching done by priests was infrequent and elementary. This new Order would provide assistance to the bishops and would move about according to the needs of the Church.

Today, as in its early days and for over 750 years, the Order is dedicated to the proclamation of the Word of God for the salvation of souls. The Dominican way of life consists of the evangelical counsels of poverty, chastity, and obedience, study as the basis for preaching, and the communal celebration of the public prayer of the Church. By these means a life of contemplation is fostered and the apostolate of preaching and teaching advanced. As the great Dominican teacher, St. Thomas Aquinas expressed it; the goal of the Dominican is ”to contemplate and to give to others the fruits of contemplation.” In the nearly eight centuries since its origin, the Order has numbered among its members theologians, mystics, Doctors of the Church, workers among the poor, popes, saints and innumerable men and women who have left less tangible traces of their work