Based on an analysis of the writer Tristan L'Hermite, this study focuses on the effects of the constraints individuals experienced in the kinship system of seventeenth-century Ile-de-France and the legal practices associated with it. Drawing on Tristan's literary and theatrical works, as well as notarial archives, this article examines his relationship with his mother and her relationship with her in-laws (both often difficult, according to Tristan). The consequences of a hypogamic alliance associated with residence in her husband's seigneurie created an indivisible inheritance that placed all involved in fragile positions. Nonetheless, Tristan, by affirming his profession as a writer, could simultaneously find an accomplished form of subjectivity and the public means for resolving these domestic difficulties.