A nun is a Religious woman under vows who belongs to a contemplative community that practices some form of cloister or enclosure. A Religious Sister is a woman, normally under vows, who is not bound to cloister or enclosure so that she is free to engage in the public ministries of the Church. Women become nuns for the life of prayer. Women become Sisters to collaborate in the apostolic life of the Church. Sisters are not un-cloistered nuns--they are and were originally meant to be--lay women who consecrate themselves to Chirst's mission in the world.
Nuns normally come from the monastic orders—Benedictines, Cistercians, Carthusians—or the Mendicant Orders—Carmelites, Franciscans (Poor Clares), Augustinians, Dominicans. Some of the later religious congregations—the Passionists and Redemptorists to mention two—also have communities of enclosed women affiliated to them. Several communities of women founded at the time of the Council of Trent who, according to the norms of Trent and its Reforms, practice some degree of enclosure are also nuns, e.g. the Visitations. The Ursulines were organized as companies of lay women, consecrated virgins, by Saint Angela Merici, but were forced to accept enclosure in the late sixteenth century, by becoming nuns. Their enclosure was never as strict as that of the mendicant or monastic nuns and by the Second Vatican Council they had been able to return to the original vision of their founder and so should be considered as Sisters.
Religious Sisters were never intended to be cloistered and date, for the greater part, from the seventeenth century. Two of the first communities of Sisters were Mary Ward’s Institute of the Blessed Virgin Mary (Loreto Sisters) founded in 1609 and Vincent De Paul and Louise de Marillac’s Daughters of Charity founded in 1633. Mary Ward had tremendous difficulty having her community recognized by the Church because they refused to accept enclosure. The community was suppressed in 1630 but the women did not disband and within nine years had revived, but it did not receive papal approval until 1703 and canonical status until 1877. Mary Ward intended her Sisters to have the same freedom to respond to the needs of the Church, especially the education of women, that Ignatius had given the Jesuits. To that end the Sisters did not originally wear distinctive garb or adopt various monastic customs.
The Daughters of Charity—because they stayed in France and flew under Rome’s radar—had a bit more success but they faced the same challenge of Mary Ward’s group in as that Canon Law at the time required women under religious vows to be cloistered. Vincent de Paul’s solution was that the Daughters of Charity would not take perpetual vows but make their vows for only a year at a time. They still renew thier vows annually. This provided the required canonical loophole. Vincent de Paul explicitly did not want his Daughters to be nuns and he gave them the following admonition:
for a monastery, only the houses of the sick,
for cell, a rented room,
for chapel, the parish church,
for cloister, the streets of the city,
for enclosure, obedience,
for grille, the fear of God,
for veil, holy modesty
Boy wouldn’t that drive the boys over in Rome crazy today—no veils, living in apartments, coming and going as they need. Well, actually most of the boys in Rome have gotten used to it as Italian Sisters are, for the most part, not unlike their American counterparts. It is some Americans—both living in Rome and here in the U.S.—that aren’t happy with the Sisters.
Other congregations were founded on like models of communities of women founded not for the purpose of prayer or monastic observance, but for apostolic work—especially among women. One of the most significant of these groups was the Sisters of Mercy founded in Dublin in 1831 by Catherine McAuley. McAuley also saw her community as a group of lay women banded together to provide assistance to women and children but it was Archbishop Murray who insisted they become a non-cloistered religious institute.
Other women were recruited to communities who, like nuns, were affiliated to the mendicant communities but whose purpose was for education or nursing. Thus various congregations such as the School Sisters of Saint Francis, the Amityville Dominicans, or the Carmelite Sisters of the Aged and Infirm—to name only three of literally hundreds—were formed. The Sisters usually wore a religious habit similar to that of the nuns affiliated to the Orders but they were not nuns, and were not thought of as nuns, because they did not have enclosure.Then there were monastic women who came to this country as nuns from the great Benedictine Abbeys of Germany, Switzerland, and Austria. Usually recruited from those abbeys by monks who had made foundations in America, the nuns arrived and found that they were needed for teaching or nursing. Consequently, while they came from cloisters in Europe, they were not cloistered here and gradually—especially with the 1917 Code of Canon Law—slid over from being nuns to being Religious Sisters. Several groups of Dominican nuns who had come from Europe also gave up the cloister and became Sisters to undertake needed apostolic work in the United States.
A final category of Sisters are groups such as the School Sisters of Notre Dame or the Religious of the Sacred Heart who were organized in Europe for educational work in the late 18th or in the 19th centuries. They too were never meant to be nuns but Sisters but, influenced by the romantic revival of the early 19th century and the love for all things medieval, adopted many of the monastic customs of the enclosed Orders and sometimes a watered down version of monastic spirituality. Monastic or mendicant nuns’ customs such as the wearing of a wedding dress and veil on the day one received the habit (and thinking of oneself as a “bride of Christ”—a monastic characteristic), or the covering of the face with a veil during communion, the sitting in choir stalls in chapel, even the breaking of sleep for a “midnight office” in chapel were borrowed by some of these communities to give their Sisters a sense of being set-apart from the laity.
A particularly interesting community of Religious Women are the Daughters of the Heart of Mary who were established in France in 1791—in the middle of the French Revolution—when the Church and its institutions were being dismantled by the anti-clerical government. Consequently the members of this Society dressed in ordinary clothes and went by the title “Mademoiselle” (Miss) rather than by “Mère” (Mother) more common among French nuns and Sisters. The Daughters of the Heart of Mary never adopted either a habit or a religious title and yet they were canonical religious.
I hope by this we can see that all this nonsense about wearing habits and not living in apartments and the dropping of the vestiges of monastic customs that never were proper for Religious Sisters is just so much hooey. These good sisters who are under attack these days by the likes of Cardinal Law and Archbishop Lori and Fat-Cat Anderson of the Knights of Columbus are what they should be and were founded to be —good and generous lay women who have given their lives to the service of women, of children, of the poor and of those who have no one else to serve their needs. You go girls.