When Napoleon ordered his army to retreat from Russia in October 1812, disaster ensued. Starving, cold, exhausted and struggling with sickness, an estimated 300,000 soldiers died. Researchers now say they have identified two unexpected diseases among soldiers who died in the retreat paratyphoid fever and relapsing fever which provide fresh insights into their plight. I think that the key thing of why [the retreat] was such a failure was the cold and the hunger and so on.