The Endurance of the Mare unravels the complex and layered histories of belonging and non-belonging that emerge from family archives shaped by classed, sexual, state, and border violence. It asks: How might retelling the past enable a radical transformation of the present? How do we grapple with the enduring legacies of systemic violence and intergenerational trauma without reenacting wounded attachments that justify nationalisms and further violence? The book follows Pena, born in 1911 in the Budjak (then Russian Empire, now Ukraine), who in the 1930s travelled as a seasonal migrant worker to the Dobruja (Romania) and was forced to stay. Alyosxa Tudor traces Pena's life to examine how the trauma of migration, hunger, sexual violence, and heterosexual kinship travels across generations and national space. Mobilizing auto-theory, speculative fiction, and historical materialist analysis, Tudor proposes a paradigmatic intervention into transnational histories, memory discourse, and political responsibility. The book connects struggles from Eastern Europe to Palestine across feminist, queer, trans, and anti-racist movements. It rejects claims to epistemic innocence rooted in experiences of past violence and instead envisions different ways to politicize the present.