On February 18, 1306, the city of Camerino signed a peace treaty with three neighboring communes (Matelica, San Severino, and Fabriano). Among its provisions was a plan for a series of marriages between the inhabitants of the four communes, which would have made a group of 140 men brothers-in-law through the exchange of 140 women. Analyzing this document and its extraordinary clause—which was never enforced and did not bring hostilities to an end—, this article examines the genesis of a gender regime in a specific historical, documentary, and relational context. Adopting a pragmatic approach to gender as a means for understanding social interactions, the article analyzes the roles elite men assigned to women of their communities in reconciliation rituals, matrimonial alliances as miniature figures of peace, and the systems established to ensure the transfer of dowries and the granting of citizenship. Under such gender regimes, women served as mediators, promoting peace in their households so that it would spread throughout the entire community. They also provided dowries and citizenship to men, allowing them to maintain their dominant role in society.