Women have served in the Catholic Church since its earliest days and inhabit unique roles within it. The women who take permanent vows devoting their lives to the church are known as sisters. Two different kinds of sisters exist: those who take simple vows and can leave their convents to offer service and those who take solemn vows, live sequestered and are called nuns. Both kinds of sisters have special functions within the church.

Prayer and Contemplation

Nuns are sisters who have taken solemn vows and are permanently bound to a monastery. Nuns are traditionally completely cloistered from the outside world; however, smaller communities that cannot function completely autonomously may allow sisters to leave to shop for food or visit the doctor. Because they do not leave or take visitors, traditional nuns spend their time in contemplation, working in the monastery, praying and studying. Sisters who take solemn vows devote their lives to contemplating and engaging in communion with God. This lifestyle is meant to preach to others by example.

Education

One of the most common services that sisters provide is education. Sects such as the Sisters of the Holy Child have historically focused primarily on providing education in a parochial school environment. In recent decades, however, the number of women entering religious orders has diminished and fewer nuns are available to teach. In the United States, parochial schools still exist and are staffed by nuns, but the majority of modern teachers are members of the laity. Sisters teach in rural communities in many countries as well as in universities.

Nursing

Nursing is another common activity for Catholic sisters. Groups such as the Sisters of the Holy Cross work in many countries in small clinics and hospitals and provide a variety of services. In Uganda, the Holy Cross order provides pre- and postnatal care, immunizations and AIDS counseling. Catholic sisters played a prominent role during the Civil War and provided medical care for both sides, and groups such as the Sisters of Charity treated cholera epidemics and established hospitals such as St. Vincent's Hospital in New York City.

Religious Ministry

In addition to caring for the poor, providing education and helping the sick, sisters also engage in missionary work and religious ministry. One group, for example, the Sisters, Servants of the Immaculate Heart of Mary, engages in evangelical ministry through prison outreach, chaplaincy and campus ministry. The Daughters of St. Paul specialize in communicating their order's mission and beliefs through modern forms of media. This group provides spiritual ministry through books, podcasts, radio, YouTube, apps and other media.