This is a study of the relationship between the institution of the double monastery and Aldhelm of Malmesbury's treatise De Virginitate ("On Virginity"). Double monasteries, institutions with monks and nuns ruled by an abbess, were important ecclesiastical foundations in early medieval Europe that functioned as centers for administration, scholarship and missionary activity. The abbesses who presided over the double monasteries were often royal widows and were integral to the ruling strategies of the recently converted Christian monarchs. I argue that the double monasteries were at the heart of a wide-ranging controversy, not merely about the legitimacy of the double monastery itself, but also about the proper limits of female authority and the appropriate relationships between religious men and women in the early medieval church. Scholars have overlooked important evidence for a defense of the double monastery which provides a rationale for female ecclesiastical power and the association of religious men and women.