In the Middle Ages, infection was often more deadly for knights than the actual wounds they received in battle.

During the medieval period, particularly between the 11th and 15th centuries, medical practitioners had no concept of the germ theory of disease. This theory was not established until the work of Louis Pasteur and Robert Koch in the late 1800s. Consequently, wounds were often treated with poultices made of dung, grease, or herbs, which frequently introduced more bacteria into the bloodstream.Battlefield conditions significantly increased the risk of infection. Knights wore heavy layers of gambeson (padded cloth) and chainmail that were rarely washed. When a weapon pierced the armor, it often dragged fragments of dirty clothing and sweat-soaked padding deep into the flesh. This created a perfect breeding ground for anaerobic bacteria like Clostridium perfringens, the primary cause of gas gangrene.Historical records from the Battle of Agincourt in 1415 suggest that many soldiers who survived the initial combat died days later from fever and systemic infection. Without sterile surgical tools, surgeons often used the same unwashed blades on multiple patients, inadvertently spreading pathogens. It was not until Joseph Lister pioneered antiseptic surgery in 1865 that survival rates for traumatic injuries began to improve significantly.Furthermore, the lack of effective antibiotics meant that even simple puncture wounds could lead to sepsis, a life-threatening immune response. Before the discovery of penicillin by Alexander Fleming in 1928, a knight's survival depended almost entirely on his own immune system. This reality made the secondary effects of combat far more statistically dangerous than the immediate impact of a sword or mace.