Another reason is that there was no science and the science that existed was mainly superstition .Diets were very bad so death from diseases associated with that. Women died in childbirth in high numbers. People died from accidents, murder, and abuse. Wars were a big cause of death. So little medical knowledge was known more people died of wounds than of the war. Infections set in and depending on where the wound was you could be dead in hours. The average life span was to about 40 years old and a person 50 was considered very old.