The Ursulines, also known as the Order of Saint Ursula, is an enclosed religious order of women that in 1572 branched off from the Angelines, also known as the Company of Saint Ursula. The Ursulines trace their origins to the Angeline foundress Angela Merici and likewise place themselves under the patronage of Saint Ursula. While the Ursulines took up a monastic way of life under the Rule of Saint Augustine, the Angelines operate as a secular institute. The largest group within the Ursulines is the Ursulines of the Roman Union.

Enclosed religious orders are religious orders whose members strictly separate themselves from the affairs of the external world. The term cloistered is synonymous with enclosed. In the Catholic Church, enclosure is regulated by the code of canon law, either the Latin code or the Oriental code, and also by the constitutions of the specific order. It is practised with a variety of customs according to the nature and charism of the community in question. This separation may involve physical barriers such as walls and grilles, with entry restricted for other people and certain areas exclusively permitted to the members of the convent. Outsiders may only temporarily enter this area under certain conditions. The intended purpose for such enclosure is to prevent distraction from prayer and the religious life and to keep an atmosphere of silence.