When we think about cloistering what immediately comes to mind are the histories of women who, for various reasons, were forced by their families to become nuns. For noble families, the dissolution of the family's state by dowry was a major concern, as was the dishonor of a marriage with a groom of inferior social status. Most of the time, instigating a daughter to join a nunnery could be a dignified way to avoid these undesirable consequences, and one of lower cost to parents, even if it would cost these women's «freedom». By the analysis of Fr. Agostinho de Santa Maria's book, entitled Historia da vida admiravel & das acções prodigiosas da veneravel Madre Soror Brizida de S. Antonio [...] published in 1701, I was able to notice that the opposite also was possible, that is to say, that the nunnery might also represent a place of female autonomy. Sister Brígida's (Brizida) case differs in many aspects from the general scenario presented above. She, then called Leonor de Mendanha, was the only heir of a very noble family; she had a rich dowry and many wooers, attracted by her « fermosura » [beauty] and virtue (or maybe by her many possessions) and her mother was eager to marry her. However, Leonor did not share her mother's feelings and decided to live her life in a very different manner. In this paper I'll attempt to analyze the strategies used by this future nun to impose her will, and I'll attempt understand the characterization of the models of female sanctity existent in this period, especially with regards to one of its aspects, that of ascetic practices. [ABSTRACT FROM AUTHOR]