This volume addresses long-term effects of democratic transitions on social movements in Italy, Greece, Portugal, and Spain. From the theoretical point of view, the main focus of reflection is on the long-term impact of eventful moments on social movements, especially the causal mechanisms through which legacies and memories of transformative protest events are produced and reproduced over time, enhancing and constraining contemporary movements’ repertoires and frames. The paths of democratic transitions set norms and institutions that affect protests in the long term. Without taking a deterministic view, we examine the ways in which the past is revisited and read anew how stories are selected, what is resilient, and what is transformed. While research on social movements started in Europe with historical work on labor movements, the impact of historical legacies and memories on social movements has not been much theorized. More in general, while there is a growing interest in memory, there is little systematic theory or comparative research on ways in which important events have long-lasting institutional consequences and are remembered by future generations. With this volume, we address this gap by reflecting on the ways in which critical junctures, especially the ones produced through mobilization from below, affect the social movements that follow. In particular, we analyze transitions to democracy as points of departure and look at the ways in which their paths—and especially social movements’ participation in them—play a role in enhancing and constraining the movements that follow.