Feudalism: The dominant social system in medieval Europe where nobility held lands from the Crown in exchange for military service while peasants were obliged to live on their lord's land giving them labor/services.
Charlemagne: King of the Franks who united most of Western Europe during early Middle Ages; he was later crowned Emperor by Pope Leo III establishing precedent for future emperors being crowned by Popes.
Napoleonic Wars: A series of wars declared against Napoleon's French Empire by opposing coalitions that ran from 1803 to 1815, leading to the dissolution of Holy Roman Empire.