This study examines an important event in the French Revolution and a defining moment in the career of its principal actor, Maximilien Robespierre: the Festival of the Supreme Being. This day of national celebration was held to inaugurate the new state religion, the Cult of the Supreme Being, and while traditionally it has been dismissed as a compulsory political event, this book redefines its importance as a hugely popular national event. Hitherto unused or disregarded source material offers new perspectives on the national reaction to Robespierre's creation of the Festival and of his search for a new republican morality. This is the first ever detailed study in English of this area of French Revolutionary history, and the first in any language since 1988 It will be welcomed by scholars and students of the period.