The essays in this collection were presented at the 2021 symposium of the Marco Institute. The authors offer new readings of Medieval and Renaissance Apocalypticism, breaking with an older model that interpreted Apocalyptic movements as marginal, paranoid and bizarre, and highlighting the expression of Apocalypticism in pragmatic concerns that informed debate and practice on matters central to Medieval and Renaissance concerns: warfare, pilgrimage, the environment, gender, genealogy, and especially the appropriation of Apocalyptic tropes in the policies and propaganda of governing rulers. The essays that open and close this collection offer meditations on the enduring legacy of Apocalypticism by focusing on the events–pandemic, political unrest, and the conspiracy theories manifest in both–that mark the historical context in which this symposium took place.