This thesis aims to present how the 1755 Lisbon earthquake influenced contemporary Europe and, more importantly, how it influenced French literature. The earthquake took place in the middle of the Age of Enlightenment and profoundly shook 18th century Europe. Having destroyed the city and decimated its population, the catastrophe moved the contemporary thinkers too. The epistolary discussion, known also by the name of querelle de l’optimisme, between Voltaire and Jean-Jacques Rousseau that followed Voltaire’s publication of his Poème sur le désastre de Lisbonne, uncovered the deteriorating relationship between the two philosophers. Whilst Voltaire, in his Poème, battled the philosophical optimism and lamented the sad fate of Lisboners, Rousseau, in his letter to Voltaire, refused to do the same. He rather focused on the distinction between the general and the particular evil. Furthermore, in his characteristic manner, Rousseau blamed humans for their suffering. However, the work that is today most closely associated with the earthquake is Voltaire’s Candide ou l’optimisme. This novella firmly stands against Lebniz’s philosophical ideas, and especially against his theory about the best of all possible worlds and against his theodicy. While the quarrel between the two men is still a part of our collective memory, one could hardly say the same for other works mentioning the Lisbon earthquake. Lastly, this thesis seeks to unveil some similarities between an earthquake and an epidemics. These similarities turned out to be particulary relevant as the world is currently battling the Corona virus.