Why, in the medieval period, alongside monastic rules, was there sometimes a need to draft constitutions that clarified or supplemented their content? These texts—suspended between norm and practice—offer a central perspective on the concrete life of religious communities and the processes of adaptation that accompanied the evolution of monastic forms of life. The investigation focuses in particular on the female mendicant community, where the tension between the evangelical ideal and the demands of enclosure generated a significant flourishing of additional constitutions, in the knowledge that the drafting of such texts was not an exclusive feature of the mendicant experience, but a widespread expression of the normative evolution of female monasticism as a whole. Through several emblematic cases—the constitutions that Cardinal Giacomo Colonna drafted for the Poor Clares of San Silvestro in Capite, those drafted by Umberto di Romans for the Dominicans, and texts intended for the Augustinian and Carmelite communities—we will seek to clarify the motivations that drove various parties to intervene and supplement the text of the Rule. In some cases, this was to fill practical gaps, in others to regulate liturgical or economic life, or to reaffirm a model of discipline and obedience consistent with their religious identity.