No man (except a priest or repairman) could enter the convent. Nuns couldn't serve a meal to anyone, not even the bishop. No woman in lays dress could live at the convent. No child could be taught or reared there. Nuns could receive no letters, messages or gifts until scrutinized by the superior.
While communities (such as Hospitallers and Tertiaries) ministered to the poor and sick, by the 11th century women religious, for the most part, lived in monastic convents where they prayed and did penance for the world's sins.
Nuns generally belonged to upper classes. Queens and noblewomen often founded religious houses on land given by their husbands. They could retire in dignity upon their husbands' death or during his lifetime (should he banish his wife to the nunnery for a more profitable marriage).
When feudal wars and crusades left many women widows, convents often became their refuge. A parent could also found a religious house and install an unmarried daughter as its abbess or prioress. If a father had too many daughters and too little money for marriage dowries, he's cut his expenses by placing a daughter or two in the convent. Girls guilty of sexual indiscretions also became convent material.
The convents subsisted on new entrants' dowries. The longer established the convent was, the more bountiful their sources of income.
At one time, women's monasteries were headed by an abbess who was religious superior and business manager. Ecclesiastically, she ranked below a bishop but above a priest. She could nominate parish priests, appoint chaplains, and issue faculties to priests to say Mass, hear confessions and preach.
- Little White Book, Diocese of Saginaw