Camus used as source material the cholera epidemic that killed a large proportion of Oran's population in 1849, but situated the novel in the 1940s. Oran and its surroundings were struck by disease several times before Camus published his novel. According to an academic study, Oran was decimated by the bubonic plague in 1556 and 1678, but all later outbreaks (in 1921: 185 cases; 1931: 76 cases; and 1944: 95 cases) were very far from the scale of the epidemic described in the novel.