This document contains summaries of key concepts from the Middle Ages including: 1) The feudal hierarchy ranging from lords to serfs and their roles. Knights were tasked with protecting estates and fighting for monarchs. 2) Differences between a fief and manor, with fiefs being estates granted to vassals and manors being lands owned directly by lords. 3) The rise of partnerships between businessmen to undertake larger ventures, and bills of exchange that allowed safer money transfer between merchants. 4) Guilds that organized artisans and merchants respectively to advocate for their interests in the growing towns and villages. Merchants had greater capital and power.