This thesis examines the origin and consequences of the French Republican calendar in relation to eighteenth-century temporality. It assesses the extent of the calendar's use, examines the cultural and political meanings that it assumed, and argues that the temporal order of society can be equally as important as its spatial organisation. It suggests that calendars are not purely neutral measures of time, but are cultural, social and political texts that can express the central beliefs of a society. As the history of the Republican calendar shows, such beliefs could be highly contestable. Unsurprisingly, the demands of a ten-day week, new nomenclature, and the calendar's association with the Terror did not lend the new style of time reckoning much popularity, except amongst confirmed Jacobins. Yet, successive regimes, in particular the post-Fructidor Directory, did attempt to ensure conformity to the new calendar. In many parts of France the calendar became a site of cultural, political and, indeed, physical conflict as local communities and officials fought over observance of the new Republican day of rest, the décadi. The speed of political events and the dramatic changes in French society, coupled with intellectual trends from before the Revolution also led to new questions about the nature of time and history defined more broadly. Although the timing of society was becoming more controlled and more precise during this period, older and often more flexible time practices still remained. Opposition to the calendar and the new temporalities was not just a consequence of political or religious sentiment, but represented communal and individual attachment to older habits. Finally, it is argued that the Revolution, the calendar, and pre-existing cultural changes helped to create a modern understanding of time, and had important consequences for the imagining of the nation.