Changes in Medieval Society Growing Food Supply Switch to horsepower The three-field system The Guilds Organization of individuals in the same business Merchants came together to keep prices up Wealth helped them gain influence over government and economy Commercial Revolution Expansion of trade and finance Town fairs Trade to foreign lands Life in the city Large amounts of credit and cash Letters of credit Banking by Jews and Christians Urban life flourishes Towns swelled with people Streets were narrow, filled with animals and waste Lack of fresh water, air and light Serfs could be free Burghers; resented interferences, demanded privileges The Revival of learning Jewish scholars translated Arabic texts Science, philosophy, law and math Technology in ships, navigation and weapons Universities Vernacular writings Thomas Aquinas and his scholastics Developed democratic institutions and traditions Keeping Order in the Middle Ages Keeping order for the more harden criminal