Two Inventions That Changed European History Over the course of world history, there have been many factors that have changed the course of Western European history. Two of those main factors were the inventions of the chest harness for the horse and the three-field system of agriculture. The harness for the horses of the early middle ages was poorly designed and needed to be changed. The early harnesses were used around the horses neck. This led to strangulation of the horses while pulling the plow. Obviously, these early harnesses needed to be designed better to better put the use of the power and spe