ABSTRACT This article uses sources from the thirteenth and fourteenth centuries to provide a systematic examination of the magistrae at the beguinage of Saint Elizabeth of Valenciennes, in which Marguerite Porete resided for a while, with a particular focus on the post-inquiry era under the governance of Béatrice de Chastel. This study shows that over the course of her more than forty-year (1322-64) career as mistress and grand mistress, Béatrice procured substantial material resources and extensive social support for the beguinage. Benefiting from her outstanding leadership, rare longevity, aristocratic origin, and vast social network, the beguinage of Saint Elizabeth did not decline after the investigation of 1323 but experienced a rapid recovery over the next half-century.