[M]edieval women’s active assumption of “time-bound commandments,” commandments from which they were legally exempt, was not a form of proto-feminism. As Baumgarten never fails to remind her readers, medieval Ashkenaz was a staunchly hierarchical and patriarchal society. Neither the halakhic authorities nor the women about whom they wrote ever questioned the categorical divide between men and women, even when they permitted women’s observance of those commandments reserved for men.
In fact, the same pious impulse that led women to break the gender boundary also led women to impose upon themselves what today would be considered gender exclusion. Particularly pious Jewish women, for instance, began absenting themselves from the synagogue in the late 11th and 12th centuries when their menstrual cycle rendered them impure. By the late 13th and 14th centuries, this became the norm for all Ashkenazi women, [although ceasing to be so in later centuries]. . . .
Baumgarten blazes a trail in the field of medieval Jewish history and law [by arguing that texts] and halakhah do not shape life and practice, but rather it is the other way around. Social custom and contemporary cultural settings led medieval rabbis to discover new things in old texts.