Twelfth-century ethics is commonly thought of as following a stoic influence rather than an Aristotelian one. It is also assumed that these two schools are widely different, in particular with regards to the social aspect of the virtuous life. In this paper I argue that this picture is misleading and that Heloise of Argenteuil recognized that stoic ethics did not entail isolation but could be played out in a social context. I argue that her philosophical contribution does not end there, but that she departs from both the stoics and her teacher, Abelard, in her defence of the ideal of moderation. By insisting that virtue must strike a mean between two extremes, she shows that Aristotelian virtue ethics were present in the intellectual life of the twelfth century.