4. You Probably Brought Diseases Home With You, If You Returned
Possibly the most dangerous element in Medieval warfare was the danger of disease. People were already aware of biological warfare and frequently employed it by doing things like using catapults and trebuchets to hoist dead animal carcasses inside a castle’s walls. They might even find a way to get a sick person behind enemy lines, to infect the entire opposing army. Also, then there was the reality of the injuries that a soldier could receive becoming a breeding ground for germs, and the person then transporting them back to his or her home.
Many Crusader soldiers who returned from the Holy Lands carried back with them diseases that they had picked up. Even if they did not suffer from the conditions, they could transport them as carriers and thereby infect communities all along the route heading back home. Couple these realities with the fact that Medieval hygiene was abysmal and sewage often ran through city streets, and you have the stage set for large-scale infections. The people probably had some level of immunity to the diseases that were common to their areas, but when soldiers returned from faraway lands and brought new illnesses, they were utterly helpless.
